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HE 

PRACTICAL 

ELECTROPLATER. 



A COMPREHENSIVE TREATISE ON ELECTROPLATING, 

WITH NOTES ON ANCIENT AND MODERN 

GILDING, AND FORMULAS FOR 

NEW SOLUTIONS. 



By MARTIN BRUNOR 



WITH ILLUSTRATIONS. 



■> 




NEW YORK: — ^ ^ 

EMILE BRUNOR, PUBLISHER, 93-97 WILLIAM STREET. 
LONDON : EMILE BRUNOR. 
1894. 






Entered according to Act of Congress in the year 1894, by Martin Brunor 
in the office of the Librarian of Congress at Washington. 



Entered at Stationers' Hall, London, 



I 




f'3 



P33 



PREFACE 



"1§N The Practical Electroplated many processes, 
(rfl the results of unremitting research by me during the 
past twenty years, are published for the first time, in the 
belief that they will be of incalculable value to the elec- 
troplating world. The arts and industries -are making 
rapid strides through the researches of those eminent in 
their various branches, and it is fitting that the trade 
to which I appeal for support in this my latest venture 
should have at its disposal those formulas and methods 
which have been of infinite value to me. 

The world is advancing, new ideas and discoveries are 
freely propagated, and ambition ever leads onward. Any 
progressive step is immediately noted and used for the bene- 
fit of the world at large. Imbued with this spirit, and as a 
friend of progress, I have thought fit to place within the 
reach of those interested the results of my investigations. 

Paris, the centre of art and intellect, aroused my en- 
thusiastic admiration for its masterpieces and its inventors, 
and stimulated me to original research, while at the same 
time my son and I received marks of hospitality and good 
feeling from Parisians which shall never be effaced from my 
memory. There it was that I had the good fortune to ad- 



iv PREFACE. 

vance by rapid strides in the industry to which I had become 
passionately attached. To Paris therefore, la ville lumilre, 
as Hugo calls it, this work is dedicated, and it is hoped that 
the reader will appreciate the sentiment which prompts this 
dedication. It cannot be denied that France is the birth- 
place and centre of modern art, that the Parisians are the 
Athenians of to-day, and that France is the worthy suc- 
cessor of ancient Greece in matters of art. 

It is confidently believed that the present work will 
meet a long felt want in the electroplating trade. Because 
I address myself to the workingman I have not endeavored 
to make a literary reputation by this work, and have there- 
fore avoided the use of scientific terms. I appeal to the 
worker, not to the scientist, though both classes will derive 
much benefit from these pages. Nigh 200 articles and 
formulas for solutions, &c, are given, and everything has 
been explained in a clear and explicit manner. It is a 
practical book for practical men, and will be found very 
helpful in any electroplating shop. 

The list of contents will enable the reader to form an 
idea of the value of The Practical Electroplater. 
Lengthy articles on ancient and modern gilding form the 
opening chapters, and much space is devoted to the best 
manner of removing the green, a matter of prime impor- 
tance to the electroplater. Almost equally important are 
the processes which are given for gilding, as brass and 
bronze gilding, dip gilding with and without the aid of a 
battery, &c; silverplating, oxidizing brass, bronze, copper, 
&c, and many other matters of interest. On the subject 
of electrotyping my collaborator is Mr. P. M. Furlong, one 



PREFACE. v 

of the highest authorities in the United States in that busi- 
ness, who has furnished an extremely able article. 

The working jeweler has not been overlooked, and 
several chapters have been devoted to the matters that 
most concern him in the conduct of his business. Valuable 
hints and suggestions will be found under the heads of 
"Refining Sweeps," "Refining Auriferous Metal," "Re- 
covering Jewelers' Waste," " Testing Gold," and " Testing 
Silver." 

Thanks are due to the following named gentlemen for 
the aid afforded me in the compilation of this work : Prof. 
F. B. Crocker, Dr. S. S. Wheeler, Mr. P. M. Furlong, Mr. 
Boby, Dr. W. H. Wahl, Mr. J. Swinburne, and my son, Mr. 
Emile Brunor. 

I must make special mention of the signal services 
rendered me by Mr. John E. Jennings for his aid through- 
out in carefully editing the matter for the press, for his 
attention to the proof sheets, and for his able translation of 
my French writing into English. 

MARTIN BRUNOR 
New York, January, 1894. 




CONTENTS 



PAGE. 

Fire Gilding, i 

Modern Gilding, .......... 5 

Electroplating Dynamos, ........ 9 

Voltmeters and Ammeters, 10 

Brunor's Perfected Dynamo, . . . . . 11 

Carbon Battery, 18 

Instructions, ........... 19 

Removing the Green, ......... 20 

Removing the Gold from the Bath, 24 

Purification of Mercury, ........ 26 

Gilding by Electricity, ........ 27 

Brass and Bronze Gilding, ........ 29 

Hot Gilding by Battery, 33 

Hot Gilding by Electricity for Brass and Copper, 36 

Dip Gilding without Battery, ....... 37 

Dip Gilding without Electricity, Matt Finish, .... 40 

Heavy Dip Gilding on Brass, without Electricity, ... 40 

Formulas for Brass and Bronze Dipping, ..... 43 

Bronze or Brass Cleaning, ........ 43 

Bright Dipping, .......... 44 

Matt Dipping, 45 

Deposition of Copper, ........ 47 

Silverplating, . . „ „ . . . . . -53 



viii CONTENTS. 

y PAGE. 

Striking Baths, 56 

Bright Silvering by Battery, ....... 57 

Dip Silvering without Electricity, 58 

Method of Oxidizing, 59 

Black Platina Oxidizing, . . . . . . . -59 

Silver Oxidizing, ......... 59 

Oxidizing Brass Articles, ........ 60 

Black Oxidizing for Brass and Bronze Articles, ... 61 

Oxidizing Copper, ......... 61 

Oxidizing Bronze Articles, ........ 62 

Lilac or Black Oxidizing, ........ 64 

Protection from Acids, ........ 65 

Satin Finish, .......... 67 

Detection of Lead in Tin, ........ 69 

Aluminum Electroplating in America, ..... 71 

Electro-Metallochrome, ........ 77 

Formulas for Brass Oxidizing, ....... 79 

Badge and Metal Oxidizing, ....... 83 

Deep Black Color, 84 

Nobili's Rings, .......... 84 

Black Color on Brass, ......... 86 

Brown Color or Bronze Barbedienne, . . . . .86 

The Galvanometer, ......... 87 

Buying a Dynamo, ......... 89 

Formulas for Britannia Metal, ....... 91 

Mixing Black Metal, ......... 92 

White Metal (Britannia) Alloy, 93 

Casting White Metal, ......... 93 

Soft Cast Metal, .......... 94 

Soft Solder, ........... 94 

Medium Solder, .......... 94 

Brass Plating, .....«,... -95 

Electroplating Plant, ... „ .... 99 

Nickel or Silver Plating Batteries, . . . . . . 101 



CONTENTS, 

The Bunsen Battery, 

The Smee Battery, 

The Grenet Battery, 

Watch Case Gilding, 

Practical Hints on Gilding, 

Double Speed Alarm Indicator, 

Preventing Rust on Steel, . 

Effects of Cyanogen on Health, 

Stripping Metals, 

Stripping Tin from Tinned Iron, 

Stripping Gold and Silver, 

Watch Case Plating, 

Foot Lathe for Polishing Watch Cases, &c 

General Rules for Electroplating 

Nickel Plating, 

Plating Directly on Iron, 

Depositing Gold on other Metals 

Gilding by Immersion, 

Recovering Gold, 

Recovering Silver, 

Black Platinum Oxidizing, . 

Weights and Measures, 

List of Materials, 

Bath for Agitating, 

Half Tone Etching on Copper, 

Etching Copper by Electricity, 

Electrical Smelting of Aluminum 

Solders for Aluminum, 

Matt Aluminum, 

Tin Plating Process, 

Platinum Plating, 

Preparing Electroplating Baths, 

Cadmium and Silver Alloy Plating 

Electrotyping, . ... 



IX 

PAGE. 
IOI 

103 
105 
107 

IOO 
III 

113 
115 
II 9 
119 

120 

121 
123 

125 
129 

131 
133 
134 
137 
138 

139 
141 

145 

147 
I49 
151 
153 
I6 7 
168 
I69 
171 
185 
189 
193 



x CONTENTS. 

PAGE. 

The Foundry, coco...,-. 197 

To the Printer, . „ . 199 

Wood Cuts, 203 

Molding from Duplicates, 204 

Molding from Plates Mounted on Wood, 204 

Molding Composition, 205 

The Molding Case, 207 

Filling the Case, 209 

Shaving the Wax Case, ........ 209 

Blackleading the Case before Molding, ..... 210 

Graphite, 210 

Washing the Form, 212 

Blackleading the Form, . . . . , . . 212 

Concave in Type, . . 213 

Molding the Form, 214 

Cutting Down the Mold, 216 

Burning Down the Mold, ........ 217 

Building Up the Mold, 218 

Connecting the Mold, ......... 219 

Blackleading the Mold, ........ 220 

Stopping Out the Mold, ........ 220 

Blowing Out the Mold, . . . . . . . . 221 

Metallizing the Mold, 222 

Striking Solution, ......... 224 

Sulphate of Copper Crystals, ....... 226 

Sulphate of Copper Solution, ....... 228 

Depositing the Shells, ........ 232 

Stripping the Copper from Old Plates, 235 

The Dynamo, 236 

Removing the Shell from the Mold, 238 

Evaporating the Water from the Wax, ..... 238 

Cleaning the Shells, ......... 239 

Tinning Solution, .....„.".. 240 

Tinning the Shells, 241 



CONTENTS. xi 

PAGE. 

Electrotype Backing Metal, ....... 244 

Backing the Shells, 244 

Cleaning the Plate, ......... 245 

Straightening the Plates, . . . . . . . . 246 

Shaving the Plates, 247 

Beveling the Plates, . . 248 

Routing the Plates, 248 

Finishing the Plates 248 

Plates Mounted on Wood, 250 

Plates Mounted on Metal, . . 250 

Nickel Facing Electrotypes, 251 

Nickel Solution, .......... 252 

Stripping the Nickel from Electrotypes, 253 

Electrical Unity, . . . . . . . . . . 254 

Electromotive Force, . . . . . . . . ; 255 

Electrical Resistance, 255 

Electrical Current, 256 

Quantity, 256 

Ohm's Law, 257 

Relative Conductivity of Metals, ...... 258 

Photo-Engraving for Newspapers, 259 

French Varnish, 261 

Transparent Varnish, . . . . . . . . . 262 

Refining Sweeps, ..... ..... 263 

Recovering Jewelers' Waste, 269 

Refining Auriferous Metal, 271 

Testing Gold, 273 

Testing Silver, . . . . . . . . . . 273 

Colors of Gold, .......... 274 

Assaying and Testing Sweeps, . . . . . * . 275 

Assayer's Weight, ......... 277 

Table of Weights, ......... 277 

Gold Assaying Report, ........ 278 

French Coloring, . ' . „ . . . „ . . . 279 



xii CONTENTS, 

PAGE. 

Electroplating with Iron and Nickel, . 281 

Electro-Deposition on Glass, ..„„... 283 

Small Outfits for Manufacturers, 285 

Utilizing the Incandescent Circuit, or Direct Current Trans- 
former, 28g 

Problem of Commercial Electrolysis, ..... 291 

Aluminum, 292 

Magnesium, .......... 293 

Zinc, 294 

Lead, ............ 294 

Gold and Silver, 295 

Electro-Metallurgy of Copper, 296 




FIRE GILDING 




HE process of gilding by fire was known to 
the ancient Greeks and Romans. Ample 
proofs in corroboration of this statement, 
which to some may seem somewhat bold, 
are in the author's possession. In several tombs discovered 
in Greece and Italy a few years ago there were found small 
hand mirrors of exquisite workmanship. These were of 
bronze, covered with a thin coat, or rather plating, of silver. 
They showed by their rare elegance of shape and the artis- 
tic finish of their handles not only the perfect taste of the 
Greeks and Romans in all things pertaining to art, but also 
the high degree of skill attained by their goldsmiths. 

The Gauls while under the Roman yoke acquired the 
civilization and artistic ideas of their conquerors, and these 
have been inherited and improved upon by their successors, 
with the result that we now have marvelous examples of 
skill and dainty and fastidious taste, which tend to uphold 
the high position French art holds. 

At the glorious epoch of the Renaissance, when the 
people awoke to consciousness after a lengthy period of 
lethargy; when liberal minds, tired of despotism and 
tyranny and scorning the threats and violence of ignorant 






2 THE PRACTICAL ELECTROPLATER. 

people, gave utterance to their noble thoughts, art, which 
had been so little followed throughout the Middle Ages, 
flourished again. 

The goldsmith's art, with all others, was ardently cul- 
tivated. Benvenuto Cellini (1500-1575), the master of 
masters, created his wondrous works of art, specimens of 
which are still preserved in the Louvre at Paris. Besides 
Cellini some of his pupils and other artists of lesser renown 
have left specimens of their work, and it must be acknowl- 
edged that many of these, now displayed in the great mu- 
seums of Europe, are veritable masterpieces. 

This dissertation is deemed necessary in order to im- 
press the reader with the fact that the art of gold and 
silver smithing is not a secondary one, but is worthy from 
all points to be considered as great, difficult, and intricate. 
We will now proceed to the description of the manner 
of operation. 

Fine gold of i,oooths is employed, which undergoes a 
process of rolling, bringing it to a uniform thickness. This 
done, it is cut into small squares, which are placed in a 
receptacle that will not break even when exposed to intense 
heat. To this gold a certain quantity of quicksilver is 
added, and the whole placed over a fire until the gold, 
under the combined action of the quicksilver and the 
heat, is completely dissolved. 

Great caution should be exercised as to the fire. The 
heat should be applied gradually ; if done suddenly the 
quicksilver will sputter. Everyone knows that the fumes 
escaping from quicksilver when heated are highly injurious. 
They affect the nerves, and the person inhaling them is 



FIRE GILDING. 3 

liable to severe nausea and cramps. Therefore the opera- 
tion should be performed in a chimney with a good draught. 

The dissolved gold may be stirred with a small rod of 
glass. It will be noticed that it has formed into a soft 
amalgam or matter not unlike butter. This amalgam or 
matter should be placed in a cloth, and well rinsed until all 
quicksilver has been pressed out. 

The object to undergo the gilding process must be 
thoroughly cleansed of all greasy matter. This is essential, 
as by omitting a thorough scouring no satisfactory gilding 
can be obtained. In the same manner any oxidation that 
may be found on the object should be removed. Nitrate 
of mercury is necessary for the amalgamation of the article 
to be gilded. This nitrate must be mixed with a solution 
of sulphuric acid, of a strength of io° Baume hydrometer. 
The article is immersed in this mixture, and when removed 
a coat of silvery whiteness has been deposited. 

Then the amalgam — the gold which has been dis- 
solved — is taken and the process of amalgamation begun. 
For this a small copper stick is necessary. This stick 
should be of spatula shape, and care must be taken to 
cover the object with a uniform coat of gold ; that is, even 
as to thickness. 

To secure a satisfactory result a bread pan should 
be used, so as to equalize and place the covering gold per- 
fectly. Thus a smooth and even surface will be obtained. 
The object covered is then exposed to the action of a fire 
of medium intensity, until heated to ioo° Fahr. 

It should be understood that the object should not be 
reddened by the action of the fire. Too intense a fire has 



4 THE PRACTICAL ELECTROPLATER. 

a tendency to make the quicksilver sputter. The danger 
of this has been explained. When the quicksilver evapo- 
rates the article should be removed. A yellowish color 
like that of gold is the result. Sometimes the article may 
not have been entirely covered with the dissolved gold ; 
in such cases a repetition of the operation becomes neces- 
sary. The article covered will then be ready to undergo 
the burnishing process. 




MODERN GILDING. 




HE history of modern gilding is not 
lengthy, as gilding by the process now 
generally employed has been commer- 
cially practicable for half a century only. 
The word galvanizing is used usually 
instead of gilding, particularly in Europe, 
where an electroplater is called a galvanizer. The word 
is derived from the name of the celebrated Luigi Galvani. 
As many are not acquainted with the circumstance it will be 
in order to narrate what led to the discovery of galvanizing. 
One day one of his pupils noticed a sudden and strange 
movement on a muscle of a frog that had been skinned, 
and which was in contact with a copper wire. Galvani 
followed up this discovery, coming to the conclusion that 
such a phenomenon could be brought about by an electrical 
machine, as every contact of the metal with the nerves 
of the muscle caused the convulsive motions. He took 
that to be the cause of the animal's electric power, the 
muscles and nerves being like the armature of a condenser. 
Volta repeated and discussed the experiments of Cxalvani, 
and formed the conclusive opinion that the touch of the metal 
caused the electricity. Galvani was born and died in 
Bologna, Italy (1737-1798). 



6 THE PRACTICAL ELECTROPLATER. 

Gilding received an impetus in the time of the cele- 
brated doctor and chemist Brugnatelli, born in Pavia, Italy, 
and professor at the University of Pavia (1761-1818). 

In 1802 Brugnatelli discovered several solutions suit- 
able to reduce or deposit the metal placed in them. After 
numerous experiments he found that the ammoniates could 
be applied in general practice, and in the year 1805 he dis- 
covered that ammoniate of gold could be deposited on sil- 
ver by means of the battery. At the time of this discovery 
the following recipe was published in the Bibliotheque 
of which Gagliardo was editor : 

" Take one part chloride of gold and add six parts 
liquid ammonia. The mixture will decompose, a sediment 
will form on the bottom, and a part of the latter dissolve 
into ammoniate of gold." 

In applying this solution a glass jar is used. The 
articles to be gilded are fixed solidly in the jar to a steel or 
silver wire, and connected to the negative pole. Any silver 
article to be gilded should always be submerged entirely in 
the solution containing the ammoniate of gold. The gal- 
vanic circuit is closed by a strong band of cardboard which 
should be dampened some time before using. This band of 
cardboard is connected to the positive pole and the solution. 
After standing for a few minutes the article will be gilded 
entirely by the galvanic current. This process was received 
with considerable favor and soon became general in most 
of the large shops. A report written by Messrs. Barrall, 
Chevallier and Henri, expert chemists, on this subject says 
that the test of Gagliardo was unsatisfactory, because the 
gilding when compounded looked like paste and would only 



MODERN GILDING. 7 

partially dissolve. A part of the gold remained and the 
subject when taken from the solution had a dirty color. 
The liquid portion of this solution was alkaline, but not 
always, as ammonia escapes very rapidly and the gold will 
deposit slowly. This gilding, said these distinguished 
gentlemen, could not be made practicable under any circum- 
stances. It is more than likely that Brugnatelli was the first 
who discovered how to gild by the galvanic process. 
Evidences were found in his laboratory which confirmed 
this opinion among the noted chemists and inventors of 
that time. 

M. de la Rive, a noted Geneva physician, made nu- 
merous experiments and tried those formulated by Bru- 
gnatelli. He tried to discover a means to prevent mercury 
gilding from spreading and engendering disease 

He remarks that he tried to pass the current of a 
powerful battery in a gold solution, by attaching a piece of 
platinum wire to the positive pole and the article to be 
gilded to the negative pole. He only succeeded in plating 
the platinum, and his efforts failed when he tried the same 
process on brass and silver. The chemical action that the 
metals had on the gold solution, when containing much acid, 
would dissolve the gold and prevent it from adhering to the 
object. In 1829 M. Becquerel, Sr., employed the electric 
current in electrolyzing silver, lead and copper ores, but, 
having in view the refining of metals, he never thought of 
applying his observations to galvanoplasty or gilding 

Galvanoplastic work was invented in February, 1837, 
by a Russian physician named Jacobi and Thomas Spencer, 
a well-known Liverpool physician. Some time after making 



8 THE PRACTICAL ELECTROPLATER. 

several experiments Jacobi discovered the solubles known 
now as the anodes or electrodes. As soon as this kind of 
work became known several eminent workers thought that 
it could be applied in a similar manner to gold plating, 
but the process could not be made practicable. It is to 
Thomas Spencer and the Elkington brothers that we are 
indebted, for they were the gentlemen who discovered that 
galvanic gilding was a possibility. As a matter of fact the 
process has been greatly improved in later years, in the same 
manner that progress has been made in every branch of 
trade, science and art. 

Henry Elkington found that alkaline solutions could 
be substituted for acid solutions, which were then in use. 
This could be done by using compounds of cyanogen and 
double salts, which are not decomposed by electro-positive 
metals. 

Jacobi says that these compounds were not unknown 
to chemists, but it was never imagined that they could be 
utilized in the manner which Mr. Elkington discovered. 

The author, who has been working steadily in this 
trade for more than twenty years, recollects an old man, 
a jeweler in his native place, who was well acquainted with 
a method of gilding by a very practical chemical process. 
It may be remarked that many believe the galvanizing 
process has been discovered within the past few years. 
This old jeweler used to gild by means of prussiate of 
potassium, to which he added, in order to produce the 
required electricity, small pieces of zinc. Both these ma- 
terials were placed in the same bath. This primitive 
method was known about seventy years ago 



ELECTROPLATING DYNAMOS. 




jYNAMO-ELECTRIC machines intended for 
electro deposition differ from all others. 
While dynamos built for the transmission 
of power or electric lighting seldom de- 
velop less than no volts of electromotive force, those 
wound for electroplating seldom give more than fifteen. 
This is because the electroplating baths are regulated 
by the quantity of current. It was formerly believed that 
the intensity regulated the rate of deposition, but this 
is erroneous, as the baths have very little resistance. 
Operators practicing electroplating have a tendency to 
cling to the notions of the nature of electricity formerly 
held. The practicability of using simpler and more correct 
terms and methods in dealing with the output of dynamos 
has, however, been shown. Thus intensity undoubtedly 
meant the electromotive force. To express the unit of 
electromotive force the term volt was used. This word 
is derived from the name of the celebrated Italian pro- 
fessor, Volta. For the quantity of the current the ampere 
was chosen as a unit. This term comes from the name of 
the French professor, Ampere. 




io THE PRACTICAL ELECTROPLATER. 

VOLTMETERS AND AMMETERS. 

Herewith illustrations are given by which the work- 
man can form some idea of the appearance of voltmeters 
and ammeters, instruments which are very valuable for 
their purposes. 




Voltmeter. 




Ammeter. 

By means of the voltmeter and ammeter the work- 
man can easily gauge or ascertain the quantity or intensity 
required for running the baths. 



BRUNOR'S PERFECTED DYNAMO. 




RIOR to entering into details it is neces- 
sary to mention that many difficulties 
were encountered before the author suc- 
ceeded in having the perfected dynamo 
built which was essential to his objects 
and aims. Numerous manufacturers 
were applied to and tried, but without success, until he 
placed his ideas in the hands of the Crocker-Wheeler Elec- 
tric Company, which at once grasped them and success- 
fully produced the machine. A meed of praise is due to 
Professor S. B. Crocker, D. Sc, and to Dr. S. S. Wheeler, 
inasmuch as it was owing to their acumen that he at length 
obtained what he wanted, the first named gentleman passing 
on the machine and testing it before allowing it to leave the 
company's premises. 

A Brunor perfected dynamo is made without regard to 
cost of material or of labor, and is so designed that it per- 
forms the regular rated work at a much slower speed than 
has been possible heretofore. It has its parts so formed or 
arranged as to prevent all the troubles which many years' 
experience has shown were liable to happen to electrical 
machinery. A Brunor perfected dynamo has many special 
advantages which cannot be found in others. The field 



12 THE PRACTICAL ELECTROPLATER. 

magnets are composed entirely of the best wrought iron, 
each magnet being forged in a single piece and set deeply 
into the base, thereby securing great solidity and ample 
magnetic contact. (See Diagram No. i.) The space for 
wire on these magnets is perfectly cylindrical, in the form of 




Brunor's Perfected Dynamo. Speed. 

Minute. 



,2oo Revolutions Per 



an ordinary spool (see Diagrams Nos. 2 and 3), thereby 
insuring smooth and perfect winding of the wire, and the 
core is short, permitting the shaft of the machine to be low 
enough to free it from vibration. By this construction 
the neutrality or freedom of the base from magnetism is 
secured, and there is no tendency to leakage. This makes 



BRUNOR'S PERFECTED DYNAMO. 



^3 



the Brunor machine far superior to all those in which the 
base is made to serve as one of the pole pieces, as the bear- 
ings then become magnetized and make the shaft bind. 

The armatures possess several improvements. They 
are sufficiently large in diameter to obtain slow speed 
(see illustration of armature), and are so designed that the 




Diagram No. i of Brunor' s Perfected Dynamo — Front View. 



wire winding is entirely embedded below the surface of the 
iron core, thus protecting it from all injury, holding it 
rigidly in position and rendering it possible for the magnets 
to approach very closely to the core, so that an intense mag- 
netic effect is produced. The armature is mounted upon a 
brass face plate, which is first turned perfectly true, and 



14 



THE PRACTICAL ELECTROPLATER. 



after completion it is very carefully balanced, so that when 
run at full speed the motion is hardly perceptible. The 
bearings are all of the self-oiling type, which do not require 
attention oftener than once in from two to four weeks. The 
arrangement of these bearings is shown in the illustration 
on page 17. 




Diagram No. 2 — Side View of Brunor's Perfected Dynamo. 



The base of the pillow block is hollow and contains 
a supply of oil which is carried over the shaft by two 
rings, which travel upon the latter and are caused to 
revolve by its motion. They carry the oil continuously to 
the upper side of the shaft. 

The bushings or brasses in which the shaft runs rest 
in turn in universal or ball joints in seats of babbitt metal 



BRUNORS PERFECTED DYNAMO. 



15 



in the pillow blocks, so that the bearings are sure to 
assume perfect alignment when the shaft is introduced. 
After the machine has run for a month the old oil contain- 
ing the grit, &c, is drawn off from the pet cock at the base 
of the pillow block. The cock is then closed and fresh oil 
introduced by removing the thumbscrew in the pillow 
block cap on the top. 




Diagram No. 3— Horizontal View of Brunor's Perfected 
Dynamo. 



The brushes are held by rocker arms which revolve 
freely around the entire circle, without fear of the brass 
connecting parts " grounding " against the frame, a great 
advantage in special work where dynamos are to be 
adapted for unusual positions. 

With the form of armature core in the Brunor dynamo, 
which reaches close to the field magnets, and the high 
grade of wrought iron used for the latter, the operator is 
enabled to maintain the magnetism, and therefore the power 



1 



16 THE PRACTICAL ELECTROPLATER. 

of these machines, with only about one-third as much wire 
as is used on the fields of any of the so-called standard 
machines. This great saving of wire not only reduces the 
weight of the machine, but materially increases its effi- 
ciency, or the amount of electricity that can be obtained 
from a given amount of power, for with less wire less power 
is required. 

The speed of all dynamos of the Brunor design is very 
low. This in many cases makes countershafting, &c, un- 




Armature — Ventilated. Constant Speed, 1,200 Revolutions Per 

Minute. 

necessary, as its designer preferred to design and construct 
the machine so as to enable it to give its full power while 
running slower than others, and because a slow running 
dynamo is much quieter, more durable, and also easier to 
take care of. The noiseless running is aided by the solid- 
ity of the base, which is of cast iron in one piece, forming 
also the yoke of the field magnets. This casting is the 
heaviest part of the machine, and therefore brings the centre 
of gravity very low, thus securing steadiness and stability. 
The proximity of the armature core to the field magnets 
renders a high magnetic pressure unnecessary, and the 
amount of magnetism escaping from the fields is thereby 



BRUNOR'S PERFECTED DYNAMO. 17 

very much reduced, so that no perceptible effect is produced 
at a short distance from the motor. 

The best double insulated wire is used throughout for 
the windings, the cores being first wrapped with vulcabeston 
and heavy canvas saturated with shellac, and the machines 
are severely tested for insulation, none being passed without 
an insulation resistance of over one megohm, and the aver- 
age is at least ten megohms. 




Detail of Self-Oiling Bearing. 

The output given by the machine in volts and amperes, 
its speed, consecutive number, &c, are all plainly marked 
upon the name plate. The "constants" of the armature, 
the number of turns, size of wire, &c, are also stamped upon 
its face plate, which is a new feature. 

The rocker arm is provided with a heavy insulated 
handle to enable all adjustments to be made without touch- 
ing the conducting parts, and the machine is heavily 
japanned in all its parts and baked at a high temperature, 
thus securing a polished surface which resists dirt and oil. 



i8 



the practical electroplater. 
Carbon Battery. 



The accompanying illustration shows how cells are 
connected, that is, in series or intensity, to get the highest 
voltage possible from the battery. However, this will not 
suit plating, as it is better to connect the cells in quantity, 




Carbon Battery. 

in order to get the full amount of current with a low vol- 
tage. The carbon here illustrated is a reduced form of the 
Bunsen. This battery is very good and strong, and pro- 
duces a strong current ; but it has a fault — its fumes tarnish 
metal and are unhealthful. 




INSTRUCTIONS. 



EFORE describing the processes of gilding and 
silvering it is necessary to review the causes 
determining the success or non-success of the 
operations. The essential qualities which 

the objects gilded or silvered by the batteries should have 

will therefore be described. 



I H I N I 



Adherence. 



The first and most important quality of a good gilding 
is the perfect adherence of the gold to the objects covered. 
To arrive at this result the surface of the pieces to be 
gilded should present certain conditions, some chemical 
and some mechanical. When the objects are submitted to 
the action of the atmosphere they are covered with a film 
consisting of air and oxide. This forms one of the ele- 
ments included in this body and determines on the metal's 
surface the beginning of oxidation, and although not seen 
it really exists. 



20 the practical electroplater. 

Removing the Green or Stripping. 

It will be understood that if the film of air and oxide 
is not removed it will prevent the coat of gold from ad- 
hering, and a species of isolation between the subject and 
gold deposited will occur. In this case the operation would 
be worthless and the labor lost. To prevent this the ob- 
jects have to undergo a stripping and dipping operation, 
which will remove all greasy matters caused by the work- 
man handling them. 

For example, take a number of gold rings after they 
have been withdrawn from the pickle, i. <?., from the dip 
of sulphuric acid and water. Every electroplater should 
know that gold is more difficult to clean than brass. The 
process which the author sets forth in this work has brought 
about some wonderful results in the United States. Several 
people have tried to discover the secret of his methods, but 
without success. The principal reason why so many platers 
fail to accomplish the best results in removing the green 
is that the current is not sufficiently strong and the solution 
not efficient. A large number of manufactories have been 
fitted up under the author's supervision throughout the 
United States, and in every instance the results have been 
very successful. 

To obtain the best results the solution and the current 
must be of sufficient strength, say not under ten volts and 
seventy-five amperes. 

Formula for the Solution. 

Every plater should be acquainted with the fact that by 
reversing the poles of the dynamo the green adhering to 



REMOVING THE GREEN. 21 

the rings can be removed ; but instead of being bright 
the latter will present a rough appearance, and in many 
cases be spoiled. To obtain the bright finish which has 
made the author's work so renowned and highly praised by 
others the following formula for the solution should be used : 

Two ounces carbonate of copper. 
A quarter of a pint of ammonia. 
One gallon of water. 
Four ounces of carbonate of soda. 

Add cyanide of potassium until 15 Baume is reached. 
This should be used when cold. The solution when used 
in small quantities may be warmed, but otherwise it should 
always be cold. Several efforts have been made by platers 
to ascertain the ingredients of this solution, but the author 
always refused to divulge them, withholding the formula 
for the present work. 

Preparing the Bath. 

After the solution has been carefully prepared it will be 
well to observe the following instructions in preparing the 
bath : 

First. — Care should be taken that the tank or jar 
be placed where the workman will be unobstructed in his 
labors. 

Second. — A bath for ordinary use should be 16x18 
inches and 15 inches deep. It may be made of wood or 
cemented stone, and then lined with an anode of copper 
sheeting about the thickness of ordinary book paper. The 
copper anode for the lining of the bath should be one foot 
in length and connected by four hooks to two crossbars, 



22 



THE PRACTICAL ELECTROPLATER. 



resting on the top of the bath. One of these bars must be 
connected to the negative pole. The hanging bar, which is 
connected to the positive pole by a flexible wire, should be 
placed on top of the bath, resting between the two cross- 
bars. For a large workshop, such as the author has at his 
disposition, the bath should be 20x24 inches and 18 inches 
deep, as exemplified by the following illustration : 




Bath for Removing the Green. 



Third. — Have a basin of some sort stationed near the 
bath, half filled with water, so that when articles are taken 
out they can be rinsed without losing any of the solution. 
This water should be poured back into the bath once a 
week or three times a month. It necessarily follows that 
a small bath will not be as efficient as a large one. The 
maximum quantity, such as the author uses, is about twenty 
gallons. 

Fourth. — In stripping or removing the green from 



REMOVING THE GREEN. 23 

rings, for instance, place them on a wire, hooked at both 
ends, being careful to see that they are not crowded or 
bunched together, for this would prevent the solution from 
doing its proper work. The little cavities in the settings will 
have a rough appearance, and the finish will be far from satis- 
factory. After the rings have been placed on the wire for 
stripping connect the latter to the positive pole, then work 
the wire to and fro after the manner of churning, then up 
and down, breaking the circuit rapidly with the hook on the 
middle crossbar, much after the manner in which a tele- 
graphic instrument ticks. If the wire be permitted to re- 
main still the rings will be black and rough when taken 
from the solution. Articles from which the green is to be 
removed should be kept in the bath from three to five 
minutes. 

By following these instructions the plater will always 
meet with excellent results. The rings when taken from the 
bath will present a sparkling and polished finish, ready for 
coloring or polishing, and the cavities in the settings will 
not require any polishing. If the green is not removed from 
the articles it will be impossible to secure a nice color, either 
by acid or battery, in places where the polishing cannot 
reach. This form of bath is indispensable for plating and 
jewelers' shops. For example, to show why it is indis- 
pensable, take an old chain which the plater wants to re- 
gild, or any old article which is chased, where the gilding is 
worn from the surface. By using this process in gilding 
and silvering the surface will be smooth and even, and the 
gold will not present a rough appearance between the links 
of the chain. The remains of the gfold will be left in the 



24 THE PRACTICAL ELECTROPLATER. 

bath and on the anode. The following illustration shows 
how rings are prepared for removing the green : 



''TMjm^^Wfr^^rrmmf 



w 



Hook for Rings, Etc. 

Removing the Gold from the Bath. 

After the bath has been in use for several weeks take 
a strip of platinum or a sheet of battery carbon, and place 
it on the hanging bar or positive pole, and let the current 
run for four or five hours without cessation. After the 
bath has remained undisturbed for about twenty-four hours, 
take out the copper anode and cut it into small pieces. 
Then take the sediment which has formed at the bottom of 
the bath in the meantime and place it in an iron basin 
of some kind, put it over a fire, and thoroughly burn it 
until the smoke disappears. Then take it and mix with two 
parts of borax and one part of carbonate of soda. Put 
it into a crucible and place it in a smelting oven. After 
it is smelted it is ready to be taken to the Assay Office. 
The author takes gold to that office at least once a month. 

It is necessary that the solution should be strength- 
ened once or twice a month. This may be done by adding 
a small quantity of cyanide of potassium. The solution 
should not be stronger than 20 Baume. If it is more than 
20 take out a small quantity and add to the solution a 



REMOVING GOLD FROM BATH. 25 

similar amount of water. It is not necessary that the solu- 
tion should always be 20 Baume ; it may be as low as io°; 
but by all means see that it never goes above 20 , because 
in that case it will spoil the article and the bath will 
not do as good work. Old solutions work better than new 
ones. The more the solution is used the better it will be. 

The importance of this cannot easily be understood by 
everyone, but it should be the constant aim of platers and 
workers in this field to improve their methods. There 
is no trade or industry that some improvements cannot 
be made in, and platers should be acquainted with any im- 
proved methods that may be discovered. The results of 
the author's labors have only been achieved after years 
of hard work and unceasing effort. The process here set 
forth has been used in his shop, and also in many others 
that he has fitted out, for many purposes, especially for 
removing old gilding from brass without spoiling the latter, 
leaving it bright and clean, and at the same time securing 
the gold or silver sediment in the bath and anode. 

The process is useful also for removing any grease or 
dirt which may be present on any oxidized articles, without 
the use of acid or any artificial means. Acids are in many 
cases hurtful to the article, the cast brass being porous. 
There are numerous formulas for removing the gilding 
from brass by acids, but they are hurtful to the article, 
leaving it in a rough and unfinished condition, and often 
spoiling the chasing. 

A new solution should be electrolyzed for from one to 
two hours by means of a strip of platinum or sheet of bat- 
tery carbon suspended from the crossbar. 



26 the practical electroplater. 

Purification of Mercury. 

The purifying of mercury is often found necessary by 
the workman, and bearing this in mind room is given to 
the process of Mr. J. W. Bruhl for this purpose, one to 
which value attaches. That gentleman takes the mercury 
and shakes it up in a flask with an equal volume of a solu- 
tion of five grains of bichromate of potash in a litre of 
water, to which a few cubic centimetres of sulphuric acid 
have been added. The shaking is continued until the water 
becomes a pure green color. A strong current of water is 
then introduced into the flask, and washes away a green 
powder. 

This process may be repeated, if needful, and the mer- 
cury is lastly agitated with water until its surface becomes 
perfectly bright. 




GILDING BY ELECTRICITY. 



Cold Process. 




.HE author has several processes for 
gilding which will give the finish 
desired, but most platers believe that 
there is only one method. For ex- 
ample, take one ounce of fine gold 
and roll it until it is as thin as possi- 
ble. The gold must then be annealed so that the grease 
can be removed. After this has been done put it in an 
evaporating dish, then add one part nitric acid, chemically 
pure, and two parts muriatic acid, chemically pure. This 
forms the mixture known as aqua regia. This preparation 
must stand for about four hours before using. Then take 
the gold and put it into about four ounces of this mixture, 
in an evaporating dish. 

Should this not dissolve the gold, add a little more of 
the mixture ; when the gold has been thoroughly dissolved, 
evaporate it on a slow fire until it has the appearance of a 
thick red syrup, always being careful that it does not sput- 
ter. Stir it occasionally, which will prevent it from burn- 
ing. If it is not stirred often it is liable to burn and then 
the chloride of gold becomes dry and will turn into metal- 



28 THE PRACTICAL ELECTROPLATER. 

lie gold. If this occurs the cyanide of potassium will be 
impeded in its action. After this operation has been fin- 
ished add half a gallon of water. Then add four ounces 
of cyanide of potassium, C. P. This should be boiled in 
water for half an hour, then taken out and one gallon of 
water added. 

Put the solution in a tank where it can be used cold. 
Should the plater have an article for gilding which is so 
large that the solution will not cover its entire surface, he 
can add half a gallon of water and cyanide of potassium 
proportionately. This will weaken the gold somewhat, but 
the finish on the article will be almost as satisfactory and 
the entire surface of the article be covered at once. It is 
understood that the deposition will be slower and the coat- 
ing thinner. By using this bath very often it will become 
weak and poor in gold. To remedy this add one penny- 
weight of chloride of gold and two pennyweights of 
cyanide of potassium ; this will strengthen the bath. The 
bath must be used with gold anodes ; and always remember 
in dipping the article to be sure and connect it instantly 
with the negative pole. If it is not connected quickly the 
cyanide of potassium will eat a small quantity from the 
surface of the bronze or brass article. If there are a num- 
ber of articles to be gilded, and the connection is not 
made quickly with the battery, the solution will be spoiled. 
The solution when spoiled will give the object a brassy 
appearance. 



BRASS AND BRONZE GILDING. 




Hot Process. 

|N gilding cast or any other kind of brass remem- 
ber that before the articles are put in the bath 
for gilding the grease must be removed. This 
is an important point and should never be 
neglected. To do this effectively use the following for- 
mula : 

One gallon of water. 

One pound of caustic soda. 

Place this mixture in an iron kettle and heat over a fire 
until it boils. It should be kept at the boiling point as near 
as possible. Articles that are soldered with tin or lead 
cannot be dipped in this solution, because the caustic dis- 
solves the tin or lead, and this will place a coating of tin 
on the surface of the brass. 

When the articles have been dipped into this solution 
drop them into an old dipping for two seconds, if at hand. 
Should the latter not be handy use old aquafortis instead, 
and move the articles quickly to and fro. Having finished 
this, immerse them in the bright dipping for about ten 



30 THE PRACTICAL ELECTROPLATER. 

seconds, then take them out and rinse quickly in running 
water. The following is the formula for bright dipping : 

Two pints of sulphuric acid. 
One pint of aquafortis. 
A small handful of salt. 
A handful of soot. 

This solution should be prepared twelve hours before 
using. If soot cannot be procured, a handful of smoking 
tobacco will do, but the former is more efficacious. After 
the articles have been taken from the bright dipping and 
rinsed in water they will be ready to be gilded. This for- 
mula is not necessary for rough objects. It should be used 
on fine goods only. For common articles a solution of 

One part nitric acid and 
One part sulphuric acid 

will answer the purpose quite as well, with a very small 
quantity of water added. The water will make the solu- 
tion bite on the brass much quicker when the latter con- 
tains very much calamine. After this has been finished dip 
the articles in a solution of cyanide of potassium dissolved 
in water in an iron or other vessel of some kind for about 
two seconds. This solution must not exceed one or two 
degrees Baume hydrometer. After dipping the articles in 
this solution rinse well in water and place them in the gold 
bath instantly. This is necessary when the plater wants a 
light coating. The cyanide of potassium and water will 
neutralize the acid in the little pores and small holes where 
ordinary water would not reach. 

It is necessary to have a thick coating if it is desired 



BRASS AND BRONZE GILDING. 31 

that the article gilded should resist burnishing. Thanks to 
Professor Becquerel we know that nitrate of mercury will 
secure adherence to gold. This is known as the amalga- 
mating solution. 

Formula for the amalgamating solution : 

Two gallons of water. 

One ounce of nitrate of mercury. 

Add sulphuric acid proportionately. 




Circular Scratch Brush. 

Mix and stir until it becomes clear. After the articles 
have been dipped into this solution they will come out 
bright, and have a silvery appearance. Should there be 
black or purple spots on the surface of the objects rub with 
a circular scratch brush or hand brush, as in the illustration. 

When the object becomes bright pass it through the 
amalgamating solution again ; then dip it for two seconds 
in the cyanide of potassium and water before putting it in 
the gold bath. Leave the article in the latter for one or 



32 THE PRACTICAL ELECTROPLATER. 

two minutes. When removed from the bath examine it, 
and if there still remain any black spots on the surface 
apply the scratch brush, as before. Dip it into the solution 
of cyanide of potassium and water (which the author calls 
"anti-oxidation") and return it to the gold bath, leaving it 
until the desired finish is obtained. Instead of using all 
these solutions in removing the grease and amalgamating, a 
bath for removing the green (see page 22) would obviate 
all this labor and be much less inconvenient. All that is 
necessary is to immerse the article in this bath for a few 
minutes and the grease and oxidation will be removed, leav- 
ing the article nice and clean. These formulas are now being 
used by most of the factories which have been fitted up in 
the United States by the author. There are some cases, 
however, where the solutions made from the above formulas 
have failed to give satisfaction. In every instance the 
author investigated the matter, and he invariably found 
that the reason the solution failed to work was because the 
new bath was not electrolyzed. It is necessary to put a 
good sheet of platinum or gold on the wires of each pole, 
and dip the poles in the solution for a quarter or half an 
hour, turning on the current. The solution will then be all 
right and do its work thoroughly. 

There is a formula for preparing ammoniate of gold, 
made by Mr. Alfred Roseleur, of Paris, the celebrated 
chemist, which is sometimes used ; but the author does not 
recommend it to his readers, as it is very dangerous and 
liable to explode on the slightest friction when dry. Am- 
moniate of gold is very dangerous when dry, and should 
it explode it will work havoc, as it is very powerful. Am- 



HOT GILDING BY BATTERY. 33 

moniate of gold is very difficult to prepare, and no work- 
man, unless possessing much experience of electroplating 
or chemistry, should ever attempt it. It is not of such an 
explosive nature when kept in a damp condition, but if 
permitted to dry it will explode on the slightest friction or 
blow. 

Hot Gilding by Battery. 

Let it be understood that the author does not care to 
make use of scientific terms in this work, nor does he aim 
to address learned men, but rather the artisan and the daily 
toiler. Nor is he striving for a literary reputation. He 
has endeavored throughout to embody his ideas in the 
simplest form, so that all can easily understand his aim. 

In hot gilding by electricity the process which is here 
given is the cheapest, the simplest, and the quickest. In 
preparing the solution for this form of gilding take ten 
pennyweights of fine gold and roll it until it has been 
reduced to a thin sheet. After the gold has been rolled it 
should be annealed until the greasy matter accumulated 
from the rolls has been eliminated. It requires only a very 
slight quantity of this greasy matter to prevent the action 
of the acids. After the annealing process the gold is 
ready to be put into the evaporating dish. Some gilders 
cut it in small pieces, but this is not necessary. 

A solution of aqua regia should be prepared a day 
beforehand to use with this, otherwise its action will not be 
so rapid. The formula for the aqua regia is as follows : 

One part nitric acid. 
Two parts muriatic acid. 



34 THE PRACTICAL ELECTROPLATER. 

This mixture should be put into an evaporating dish 
and then placed in the open air or in some location where 
there is a good draught, because the fumes thrown off are 
very obnoxious and injurious to health. After the acid has 
dissolved the gold place the vessel in which it is contained 
over a slow fire and boil until the solution has the appear- 
ance of red syrup. Always be careful that the heat does 
not become too intense. 

Gold in the pure state will give two and a half times 
its value in chloride of gold ; that is, ten pennyweights of 
fine gold will furnish twenty-five pennyweights of chloride. 
Should the acids be concentrated when the mixture of aqua 
regia has been made, add a small quantity of water and the 
gold will dissolve more rapidly. 

Formula for hot gilding : 

Three gallons of water. 
Ten pennyweights of gold. 
Two hundred pennyweights cyanide of 
potassium. 

Before using the bath in which this solution is placed it 
should be electrolyzed with two platinum or two gold 
anodes. One of these should be attached to the positive 
pole and the other to the negative pole, and then immersed 
in the solution. The battery should be turned on for about 
fifteen minutes. This bath can be used daily for plating 
gold jewelry. 

This solution is suitable for coloring fine jewelry, such 
as Roman coloring and satin finishing. When exhausted it 
can be used for plating small brass and bronze articles, be- 



HOT GILDING BY BATTERY. 35 

cause those metals are much easier to gild than gold. A 
very small current will do the work efficiently. 

When the solution gives out in working on brass arti- 
cles it can be made to give a fourteen karat finish by 
adding a very small quantity of cyanide of copper, twenty 
pennyweights of bisulphide of soda, and four ounces of 
caustic soda to every gallon. 



Bath for Hot Gilding by Electricity. 

In plating watch cases, chains, etc., use the fourteen 
karat anodes. Watch cases should be highly polished 
and run through a bath of hard caustic soda for the pur- 
pose of removing the grease before being placed in the 
bath. Then pass them for a second through a light cya- 
nide and water solution. 

Remember that if this solution is expected to do good 
work it must be kept near the boiling point, and partic- 



36 THE PRACTICAL ELECTROPLATER. 

ularly for the fourteen karat finish. When it is entirely 
exhausted pour it into the bath for removing the green 
from gold (see page 22). By doing this the gold and 
chemicals will be saved. 

Hot Gilding by Electricity for Brass 
and Copper. 

It has been previously remarked that where cyanide of 
potassium is allowed to concentrate in the solution for gild- 
ing on brass and copper it will eat a very small quantity 
from the surface of the article to be gilded. As a matter of 
fact this quantity would be very small on a few articles, 
barely perceptible to the eye, but if there were many articles 
this amount would be quite sufficient to change the tone of 
the gilding. 

Formula for hot gilding by electricity : 

Ten pennyweights of gold. 

Forty pennyweights cyanide of potassium. 

Fifty pennyweights bisulphide of soda. 

One pound phosphate of soda. 

Three gallons of water. 

This solution, which is used by nearly all Paris electro- 
platers, should always be kept as near the boiling point as 
is possible. When the brass is bad, or porous, and contains 
much tin, it is advisable to dip the subject for, say, from 
two to four seconds in the cyanide of copper solution, 
and electrolyze with a slow current until a very fine coat- 
ing of copper is obtained. Rinse it well and dip into the 
gold bath immediately. 



DIP GILDING WITHOUT 
BATTERY. 



¥ 



^HERE are several formulas for dip gilding with- 



y I y out using the battery. All of these have given 
J1L a certain satisfaction, but the author herewith 
gives his readers a formula for dip gilding without the use 
of the dynamo or battery which will do the work much 
quicker, give better satisfaction, and is a great deal cheaper. 
One pennyweight of gold will plate from six to eight 
pounds of brass and give the object a nice finish, the 
color being clear and bright. There are many people, 
it is true, who have an idea that there is little to be learned 
from books on scientific and mechanical subjects, but the 
author of this work holds a contrary opinion. There is 
knowledge to be obtained from books on every subject, 
no matter how difficult or intricate the questions, just the 
same as from every other source. The reason so many 
people cannot apply the knowledge they derive from 
books is because they lack the inventive faculty. For in- 
stance, workmen may be told how to perform a certain thing 
or execute a piece of work, but to save their lives they 
cannot do it. Many times they will do -the very opposite. 
This is the one great reason why hundreds of mechanics 
and other workers only reach a certain point and never get 



38 THE PRACTICAL ELECTROPLATER. 

any further. The arts and industries are yet in their infancy. 
New discoveries and new inventions are being made every 
day, and could the people of a hundred years ago come 
back to-day they would be as much astonished at seeing the 
progress which has taken place in the interim as we are 
at the lack of progress of their time. 

The following is the formula for dip gilding : 

One ounce of gold. 
Eight ounces cyanide of potassium. 
Eighty ounces caustic potash. 
Twenty ounces bicarbonate of potash. 

Formula for chloride of gold dip gilding without dyna- 
mo or battery : One ounce fine gold, dissolved in two parts 
muriatic acid and one part nitric acid. 

Mr. Elkington gives a recipe of half muriatic and half 
nitric acid, with distilled water of the same quantity added. 
The author simplifies this by leaving out the distilled water, 
and considers that two parts muriatic and one part nitric 
acid are far more effective. After this mixture has evap- 
orated, and reduced the gold and chloride of gold, the 
solution will resemble a thick red syrup. Then take a cast 
iron steam kettle which is capable of withstanding a high 
temperature. If this kettle is new and has never been used 
clean it out with muriatic acid and scratch it thoroughly 
with a steel hand brush. Old goldplating should then be 
boiled in this kettle for, say, one day. It is better to take 
an anode of platinum, suspended in the middle of the kettle, 
and connect it with the positive pole and join the negative 
pole to the kettle ; then let the current run a short time 
until the kettle is gilded on the inside. 



DIP GILDING WITHOUT BATTERY. 39 

After this has been done take out the old gilding and 
add from four to five gallons of water to every ounce of 
fine gold. Before doing this place in a vessel of some kind 
from eight to ten ounces of cyanide of potassium and one 
gallon of water ; then put the chloride of gold into this 
vessel slowly, stirring with a glass rod until it is dissolved 
and the water becomes clear. After this take eighty 
ounces of caustic potash, twenty ounces of bicarbonate of 
potash and the mixture of cyanide of potassium and water, 
and mix in the kettle with four gallons of water and let 
boil a short time. Then the solution is ready for gilding. 

It is necessary to repeat that the brass or bronze 
articles must be thoroughly cleansed and highly polished 
and the grease removed before being dipped into the solu- 
tion. Articles that cannot be polished should be passed 
through the bright dipping. They will then be ready for 
gilding. 

Should the bath become weak, take some chloride of 
gold and mix it with water, stirring it frequently, taking 
care that it is not spilled, and pour it into the kettle. It 
depends on the amount of work the bath does. Should it 
be used a great deal it is necessary to add this mixture to 
the solution every one or two days. Then about five 
pennyweights of cyanide of potassium should be added to 
the bath every month, or once in three months. This 
will keep the bath in its proper condition. It will be well 
also to add about half a pound of caustic potash every 
three months. The author generally uses the bath at from 
50 to 8o° Baume. Be sure and have a vessel of some kind 
near the bath, partly filled with water. This water should 



4 o THE PRACTICAL ELECTROPLATER. 

be poured back into the bath every time it is necessary to 
fill up the kettle. 

Dip Gilding without Electricity, Matt Finish. 

There is a formula for dip gilding without electricity 
which has been used successfully by Professor Becquerel. 
It is a practical process and there is no hesitation in recom- 
mending it to platers in general. 

The formula for this kind of gilding is as follows : 

One pennyweight chloride of gold. 

Five pennyweights yellow ferrocyanide of 

potash. 
Twenty ounces of distilled water. 

This should be carefully prepared and then filtered, so 
that the cyanide of iron can be separated. To this add a 
mixture of potassium and prussiate of potash. 

This will give to the first solution a dull looking matt 
color. To overcome this add two parts of water, after 
which the matt will become clear. Should it not, add a 
little more water. 

The solution will always be much better if it contain 
more water and less iron. To make the matt appear, the 
articles should be washed with water acidulated by means 
of a small quantity of sulphuric acid. In order to remove 
the non-adhering deposits, rub lightly with a cloth dipped 
in the solution. 

Heavy Dip Gilding on Brass, without 
Electricity. 

On account of the thinness of the coating dip gilding 
cannot be applied to articles other than small brass imita- 



HEAVY DIP GILDING ON BRASS. 41 

tion jewelry. Yet there is a method by which the dip 
gilding can be made solid enough to compete with gilding 
by electricity. It consists in dipping the articles several 
times in a certain way. After gilding immerse them in the 
amalgamating solution (see page 31), and then rinse and 



Kettles for Dip Gilding. 

dip in the gilding again. These operations must be per- 
formed several times, until the articles are sufficiently gilded. 
It will be understood that after each immersion in the 
amalgamated solution a film of mercury is deposited on 
the articles, which is in turn dissolved in the gold dip 
and leaves another film of gold. In performing this oper- 
ation it is possible to gild large pieces, such as chande* 



42 THE PRACTICAL ELECTROPLATER. 

liers, clocks and ornaments, which are usually gilded by 
electricity. 

On page 41 an illustration is given of two iron 
steam kettles, one of which is used for dip gilding and the 
other for hot water. After the goods have been immersed 
in the dip gilding kettle dip them in the hot water contained 
in the second. If the latter commences to concentrate 
cyanide and gold take the water out and put it in the dip 
gilding. Then renew the hot water. This water must be 
changed at least twice a day. The changing depends on 
the amount of work to be done. The foregoing remarks 
apply to the solution for dip gilding given on page 38. 

It must be borne in mind that every piece of goods 
must be rinsed in cold water and afterward in hot water, 
besides the two connected kettles. They are then ready to 
be burnished, as the last rinsing in hot water removes the 
cyanide of potassium from the surfaces of the goods. If 
the cyanide is not removed the articles assume a dull color 
in a few days. 




FORMULAS FOR BRASS AND 
BRONZE DIPPING. 




Bronze or Brass Cleansing. 

,HE solutions given under this head are the most 
important for the removal of grease. Caustic 
soda is preferable to caustic potash. The fol- 
lowing is the solution for bronze or brass cleansing : 

Water, one gallon. 

Caustic potash or caustic soda, one to one and 
a half pounds. 

To cleanse bronze or brass a cast iron vessel is neces- 
sary, and the lye should be kept nearly boiling. The 
object should be immersed about ten minutes, and if soft 
soldered it should not be allowed to remain in such a 
strong lye, as caustic soda dissolves the tin contained in 
the solder, and this will tin the brass. 

For this kind of work half a pound of potash to a 
gallon of water will be sufficient. If the articles are 



44 THE PRACTICAL ELECTROPLATER. 

blackened by fire or oxidized, they should be pickled in a 
lead lined tank containing a solution of 

Water, one gallon. 

Sulphuric acid, 66°, half pint. 

If this does not act upon the metal the solution 
should be reinforced with sulphuric acid until the oxidation 
has disappeared. The article should then be placed in a 
bath of aquafortis to remove the calamine, and will come 
out with a dull color after it has been dipped in a bath 
made twenty-four hours previously. 

Bright Dipping. 
The solution for this is as follows : 

Two pints sulphuric acid. 
One pint aquafortis. 
A small handful of salt. 
A handful of soot. 

This solution should be left to cool for at least ten 
hours before using. If it has been used continually 
throughout the day a pound of sulphuric acid should be 
added to a proportion of twenty pounds of the remaining 
liquid. Then it should be left overnight to settle, after 
which it ought to be decanted into another vessel and the 
crystals of copper and zinc cast aside. A fresh solution 
may be made if desired and the first one mixed with it, 
which will be found advantageous. 

If soot cannot be procured a handful of smoking 
tobacco will do, but the soot is more efficacious. The 
object should be rinsed with running water, after which 
it will be ready to be either gilded, silvered, lacquered or 
oxidized. 



STRIPPING NICKEL. 45 

Matt Dipping. 

If a matt or satin finish is wanted without the use of 
the brush or sand blast a bath should be made of 

Two pounds of nitric acid. 
One pound of sulphuric acid. 
One-eighth of a pound of sulphate of zinc, 
And as much of salt. 

Put the mixture into an earthen jar, which should be 
placed in hot water ; stir the object in this solution until 
it has a uniform matt ; as it will come out with a dull color 
it should be rinsed and put into the bright dipping. It is 
then ready to be gilded, silvered or lacquered. 

Stripping Nickel from Plated Work. 

It is essential to entirely remove the old coating when 
articles that have been nickeled are to be replated, because 
nickel will not adhere to a deposit of the same metal. 
When it is desired to strip nickel from work that has been 
nickeled a solution for stripping the nickel from the copper 
is the first requisite. A 10 gallon bath for this purpose 
should be made as follows : 

Ninety-six fluid pounds of oil of vitriol. 
Twenty-four fluid pounds of nitric acid. 
Three gallons of water. 

The oil of vitriol must be added gradually to the 
water. Do not add the latter to the vitriol, which is a dan- 
gerous proceeding. When the solution has become cool 



46 THE PRACTICAL ELECTROPLATER. 

add the nitric acid and stir with a wooden paddle, and when 
the mixture is cold it will be ready to use. 

The articles to be stripped must be attached to thick 
copper wires and hung in the solution about a minute. 
The nickel will then be entirely dissolved, after which the 
goods should be rinsed in cold water. 

The operation thus outlined should be carried out in 
the open air, or the bath should have a ventilator or hood, 
to which is attached a pipe to carry off the fumes of the 
acid. 




Deposition of Copper 

FROM A 

Sulphate of Copper Solution. 



^=^HE author is somewhat diffident about relating 
y his personal experiences, but when platers and 
a other workers in this line understand how many- 
years he has labored in perfecting the processes given in 
this work they will pardon the digression. How many men 
in all walks of life have gone through the world eking out 
a poor existence simply because there was no one to point 
out the way to success ? How many unfortunates have 
dropped by the wayside, simply because they failed to start 
in life with a purpose ? The object of this chapter is to en- 
courage the youth who is seeking to place himself in life 
where he can be of use to the world and obtain knowledge 
by which he can always make a good living. 

The remark is frequently made that "the trades and 
professions are overcrowded." This is utterly absurd. Could 
anything be more nonsensical ? There is no walk in life 
to-day but what is always demanding men who are willing 
to work. Nothing is accomplished without work, and the 
men who make remarks of this description are those who 
lack that perseverance and continuity of purpose which in 



48 THE PRACTICAL ELECTROPLATER. 

the end wins in every vocation, no matter how humble or 
how exalted. The simplest laborer is a potent factor in the 
world and is part and parcel of the whole. He contributes 
to the education and advancement of the race as well as 
the banker and the millionaire. There is just as much 
happiness to be found beneath his roof as there is in the 
gilded palace, and ofttimes more. Life is full of opportu- 
nity, and if the men who are out of employment in the 
great cities to-day would try and find a purpose there would 
be a far better world. There would be less misery, less 
poverty, and less of the grinding oppression which hovers 
over the working classes in these days. Talent and genius 
are to be found in many a humble home, but they never 
come to light, because they have not been unearthed and 
developed. 

The author was the manager of Mr. Andrew Rosso- 
witch's celebrated electrotyping establishment at Trieste, 
Austria, for several years. While there he worked on the 
famous collection of galvanoplastic wares now located in the 
National Museum at that place. This collection consists 
of flowers, leaves, crustacean objects, and works of Benve- 
nuto Cellini and masterpieces of modern sculptors. Some of 
these articles were copied from nature, while others were 
simply coated with a shell of copper. It is in order to 
describe how the articles were prepared before putting them 
in the depositing bath. Take, for instance, a medal ordered 
to be copied ; cut a piece of gutta-percha into minute pieces 
and boil them in hot water until they become soft like 
paste ; then take this substance out and knead it with the 
hands until the air and water have been removed. This 



DEPOSITION OF COPPER. 49 

should be done as quickly as possible, to prevent it from 
hardening. The medal is then placed in a collar of iron, 
and the gutta-percha worked in and pressed until it becomes 
cold. The medal will then separate from the mold easily. 
The chasing and surface are washed with a little alcohol 
and then cleaned with a watchmaker's brush soaked in 
the fluid. 

A paste is made with a little plumbago and water, and 
then rubbed on the surface of the mold with the brush until 
a bright polish is obtained. It is then rinsed with water at 
high pressure. After this it is ready to be dipped in the 
bath. 

There is another way to make molds out of gutta- 
percha, by mixing in a tenth part of grease and gutta- 
percha and then melting. The medal or other article is 
slightly oiled and the melted mixture is then thrown on 
to the medal. It should be left to cool and afterward 
separated from the mold. This method may be used when 
a press is not handy. Should the molding fail to come 
perfectly it is because air bubbles have formed. The 
medal must be rubbed with oil again and heated as before, 
pressing it with the hand. For covering wax flowers, in- 
sects or representations of animals with metal the above 
method cannot be used, as such objects are very delicate. 
They must be soaked in a solution of alcohol and water of 
equal proportions. To this add as much nitrate of silver 
as it will dissolve ; then let it dry in a place where there 
is plenty of light. It should be put in the depositing bath 
very carefully, in order to keep the nitrate of silver from 
shaking off. 



50 THE PRACTICAL ELECTROPLATER. 

The solution for the deposition of copper should be 
as follows : 

Dissolve some crystals of sulphate of copper in a 
quantity of water. Let this stand until a Baume hydrom- 
eter shows that 15° has been reached. When the sulphate 
of copper has been thoroughly dissolved, then increase 
the solution to 18 Baume by adding sulphuric acid. Above 
all things see that the hydrometer does not go over 20 . 
The sulphate of copper should not be put in the same 
vessel containing the water. The best method is to put 
it into some kind of porous bag and leave the latter 
suspended just beneath the surface of the water. When 
arranged in this way the sulphate of copper will dissolve 
much quicker. This process can even be made quicker by 
using hot water instead of cold, but the latter is far more 
preferable. No dust or dirt of any kind should be allowed 
to get into the solution, and particularly anything that will 
conduct electricity, because it will make a deposit on the 
cathode and leave an imperfect finish. Plumbago, for 
instance, is very detrimental to the solution. 

It is not good to have the molding and metallizing 
done in the same room where the bath is located. Should 
a thick deposit be desired, it will be necessary to remove 
any excrescences with a file during deposition. 

The electromotive force essential for working depends 
on the distance the current has to traverse in passing from 
the anode to the cathode, and also on the speed of deposi- 
tion desired. When the anodes and cathodes present flat 
surfaces to each other it may be necessary to draw them 
together. Should the surface of the cathode be very 



DEPOSITION OF COPPER. 51 

irregular, having high projections and deep holes, and it is 
found difficult to shape the anode to conform to them, see 
that the latter is placed farther away from the cathode. 
In such cases take a piece of thin wire and thrust it in the 
holes, and connect this wire with the conducting wire. The 
author places the two in positions making as little differ- 
ence as possible in the thickness of the deposit on various 
portions of the cathodes. This arranges them so that the 
parts that are nearest will gather the heaviest deposit. 

If the solution is allowed to remain quiet it will take 
more time for the copper that is reduced from the anode 
to circulate evenly. 

If a strong current is forced through the solution the 
stratum near the anode will in a short time be overloaded 
with copper, while that near the cathode will be poorer. 

There are times when a quick deposition is wanted. 
To secure this the solution should be kept active, so that 
the sulphate does not accumulate in one place. If this is 
not attended to the object will have a thick deposit of cop- 
per on the corners or projections nearer the anode, and the 
chasing and deep cuts will be bare. A good circulation 
can be established by several mechanical devices. 

The current which should be used when the solution is 
at rest ought to be from ten to fifteen amperes for every 
square foot of cathode surface, especially if a very fine and 
smooth deposit is wanted. When a perfect circulation of 
the solution is kept up as much as 100 amperes per square 
foot can be utilized. 

While an electromotive force of three-tenths of a volt 
is sufficient to pass a current of from ten to fifteen amperes 



52 THE PRACTICAL ELECTROPLATER. 

for every square foot, it will require two and five-tenths of 
a volt for a current of ioo amperes for the same surface. 

In the first case one and a half ounces of copper are 
obtained every hour at the rate of the two hundredth and 
seventh part of a horse power. In the second case the pro- 
duction of the copper reaches four ounces at the rate of 
one-third of a horse power. 

If a great amount of copper is expected from a small 
quantity of current, it will be necessary to connect a large 
number of vats, with plenty of surface exposed in every one 
of them. To be more explicit : There are say, forty-eight 
cells connected in series, containing 200 square feet of sur- 
face, the anodes as well as cathodes, and placed two inches 
apart. If a current of 2,400 amperes is employed it will 
require sixteen volts to force this current through the 
circuit. Seven or eight pounds of copper will be deposited 
in each cell every hour, or 336 and 384 pounds will be 
deposited in the whole number, according to the state of 
the solution. These vats should always be constructed of 
well seasoned wood and be lined with lead. The joints 
should be made by what is called the burning process, 
which means that the edges must be joined together by 
soldering lead on the joints with a blowpipe. A plant 
of this magnitude by being kept in operation day and 
night will produce a copper deposit of from 8,000 to 
9,000 pounds. To operate such a plant requires fifty-five 
horse power. 



SILVERPLATING. 




ILVERPLATING is without doubt one of the 
most useful and important branches of electro- 
plating. It is useful because there are innumer- 
able objects to which it can be applied ; it is important 
because it prevents the metal from corroding. If brass 
and other articles were not silverplated their use would 
entail bad effects on the health. Silverplating is of par- 
ticular advantage in these days when tableware is in wide- 
spread use. 

Silverplating was discovered in the year 1840, when 
George Richard Elkington, the well-known English electro- 
plater, took out a patent at Birmingham in England, this 
leading to its general use. Several experiments had been 
made prior to that time, but with little or no success. A 
peculiar coincidence occurred when Mr. Elkington secured 
his patent. His brother Henry was also a plater of con- 
siderable skill, and something of an inventor. The same 
day that George Elkington secured his patent for silver- 
plating his brother took out another making goldplating 
practicable, and the two brothers congratulated themselves 
upon their unusual good luck. When the discovery of sil- 
verplating was announced chemists and inventors in all 
parts of Europe began experimenting, with the hope of 



54 THE PRACTICAL ELECTROPLATER. 

making other discoveries, but without success. Among the 
inventors was Henry Ruoltz, of Paris. He took out sev- 
eral patents for gilding and silverplating, but they were all 
similar to those of George and Henry Elkington. He was 
not the first discoverer of either process, as many people 
believe. Mr. Ruoltz, however, unearthed a number of use- 
ful rules which have aided both gold and silver plating to a 
great extent. In the first case he found that the electro- 
negative elements of solutions ought not to have any 
action on metals to be plated, that is elements which are 
transferred by the galvanic current to the negative pole, 
and that they should not in any way attack metals which 
are connected to it to be plated. Even the solutions must 
not corrode on metals to be plated. Second — The solution 
while under the influence of the current should not deposit 
any foreign substance on the article to be plated, but only 
the metal which is an ingredient of the solution. Third — 
The solution must be a good conductor of electricity. 

We are indebted to George Richard Elkington for 
the discovery of a process enabling the world at large 
to use cheap silverplated ware without fear of verdigris. 
He replaced acid solutions by alkaline solutions and used 
compounds of cyanogen and other double salts which 
are not decomposed by electro-positive metals. These 
compounds, says Jacobi, were not, it is true, unknown to 
chemists, but they were not recognized as being applicable 
to the industry. The Brunor formula for silverplating is 
very simple. It can be made very easily and has much less 
inconvenience than other solutions. It is as follows : 
Take one ounce of silver and place it in an evaporating 



SILVERPLATING. 55 

dish or Florence flask. Add a small quantity of nitric acid 
and heat the mixture over a slow fire. When the silver is 
dissolved it has become nitrate of silver. Have a jar handy 
with water in which there has been dissolved a handful 
of salt, and place therein the nitrate of silver, which 
then becomes of the consistence of white cheese. This 
is chloride of silver. If the water is as white as milk it is 
proof that all the silver has not settled. Add more salt 
and stir the liquid to dissolve it, and let it settle until the 
water is all clear. Allow the silver to settle at the bottom, 
throw away the water, and retain the sediment, chloride 
of silver, which must be washed many times until the 
nitric acid and salt have disappeared, leaving the chloride 
of silver in its pure state. A Baume hydrometer when at 
zero will show that the nitric acid and salt have disap- 
peared. The washing must be done in a dark place, not in 
a light one ; otherwise part of the silver will be turned into 
a fine dark blue powder which will disappear in the washing. 

When the chloride of silver has been obtained add as 
much pure cyanide of potassium as it is possible to procure. 
For every three ounces of silver add a gallon of water. If 
possible boil the solution for half an hour before using it. 
This is done in order to mix the solution thoroughly. When 
it is cold it is ready to be used. It must be above 6° Baume 
and not over 20 . 

If the anode consisting of pure silver turns black 
during the plating process cyanide of potassium must be 
added. If it should turn white more chloride of silver is 
requisite. 

When the anode turns gray at work, and white when at 



56 THE PRACTICAL ELECTROPLATER. 

rest, the solution is in good condition. The electromotive 
force employed for silverplating need not be higher than 
two and a half volts, if the average distance between 
anode and cathode is not more than six inches. 

To give the first thin film on articles made of a base 
metal, an operation termed " striking " by the trade, an 
electromotive force of five or ten volts is desirable. 

As it would be expensive to employ two dynamos, one 
for " striking " and the other for plating, it is better to 
use a dynamo capable of producing current at an electro- 
motive force of ten volts, and use four tanks connected in 
series for plating, and a fifth one for "striking," connected 
in desired circuit with the other four. This arrangement will 
give ten volts for " striking " and two and a half volts in 
each cell reserved for plating. A current of ioo amperes 
can deposit twelve ounces of silver per hour. A strength 
of five amperes per square foot of surface is generally 
employed. 

" Striking" Bath. 

Every bath must be connected with the switchboard, 
so that the plater can regulate the current as necessary. 
The term " striking " is used habitually in connection with 
britannia metal and german silver and for any other metal 
that is found to be hard to plate, such as composition 
metal. The following is the formula for the " striking " 
bath: 

For every gallon of water add one ounce of silver and 
cyanide sufficient to bring the solution up to io° or 12 
Baume. The britannia metal should be well cleaned by 
means of a circular brush and fine pumicestone prior to 



BRIGHT SILVERING BY BATTERY. 57 

being placed in the solution. The article to be dipped must 
be placed in the solution by means of a hook connected 
with the negative pole, and the silver with the positive pole. 

If the article is hollow hold the anode in the hand and 
place it in the vessel, taking care, however, not to touch the 
bottom. The two poles should not be connected. The 
anode must be kept in position for from five to ten seconds. 
Then take it out and pass it around the subject from ten to 
fifteen seconds, at a distance of two inches. It will then 
be ready for immersion in the silver bath. 

The method of procedure is not the same as regards 
german silver, which is a very difficult metal to plate. 
Every plater has much trouble in securing the adherence of 
gold or silver to that metal. If it is desired to secure the 
adherence of the plating it is necessary to use the solution 
given on page 31 and place the article in the bath for about 
a minute for the purpose of removing the green (see page 22). 
Move the article to and fro in the bath for a minute and 
then place it in a solution of nitrate of mercury. Then put 
it in the "striking" bath for from fifteen to twenty seconds. 
It will be ready after this to go into the silver bath. 

Bright Silvering by Battery. 

It will be found in the majority of cases that the sil- 
vering obtained by means of the cyanide solutions will be 
dull, and the articles when taken from the bath will inva- 
riably have a rough and unfinished appearance. This fault 
can be overcome and the subject have that bright and sil- 
very finish so necessary for artistic work. 

Numerous experiments were made to find a means of 



58 THE PRACTICAL ELECTROPLATER. 

getting a perfect finish, resulting in failure, however, until 

bisulphide of carbon was tried. This brought about success 

and gave the fine finish which is now universal. The 

formula for bright silvering is as follows : 

Two gallons cyanide of silver solution. 
Five pennyweights bisulphide of carbon. 

This should be put into a bottle, tightly stoppered, and 
left standing for twenty-four hours. At the expiration of 
that time a black sediment will have been deposited. Then 
pour off the liquid slowly and throw the sediment away. 
Clean the bottle thoroughly, pour the liquid back into it, 
and set aside on a shelf until needed. When used it should 
be mixed with the cyanide of silver bath, pouring in about 
one teaspoonful to every gallon. It will always be found 
that the articles when dipped will come from the bath hav- 
ing a bright silvery finish, looking as if they had been finished 
by means of a scratch brush. 

Dip Silvering without Electricity. 

There are numerous varieties of silverplated jewelry 

which always find a ready demand. These goods are of a 

light quality, and for a comparatively small sum a large 

quantity can be plated. The formula for plating this class 

of jewelry is as follows : 

Eleven ounces caustic potash. 
Seven ounces cyanide of potassium. 
One ounce of silver reduced in chloride. 
Two and a half to three gallons of water. 

In using this mixture place it in an iron steam kettle, 

in the same manner employed in applying the dip gilding. 

This solution is capable of plating hundreds of pounds of 

jewelry per day. 



METHODS OF OXIDIZING. 




Black Platina Oxidizing. 

^HE process of oxidizing by use of chloride of 
platina has only been in use a comparatively 
short time. It is used in plating silverware, and 
articles to which it is applied must have either a triple or 
quadruple plating. Before the article is dipped into this 
solution all greasy and extraneous matter should be re- 
moved by means of the scratch brush. Formula : 

One ounce chloride of platina. 
One pint tincture of ferrichloride. 

Oxidizing can be done without the tincture of ferri- 
chloride, and a small quantity of nitric acid may be sub- 
stituted for it, but the tincture helps considerably in 
economizing platina, and is therefore to be recommended, 
The solution should be put into an evaporating dish, and 
kept hot. Should the article, after dipping, fail to have 
the proper finish, repeat the operation. When the black 
finish has been obtained, buff the subject until it has a fine 
polished appearance, like ebony wood. 

Silver Oxidizing. 

In silver oxidizing it is very easy to imitate antique 
silver. To prepare this solution take a pint of water, one 



60 THE PRACTICAL ELECTROPLATER. 

ounce of sulphate of potash, and heat in an evaporating 
dish. After the mixture has been warmed add one or two 
teaspoonfuls of ammonia. Dip the subject into this solu- 
tion until it assumes the colors of the rainbow. After this 
the finish will turn to a black steel color. When this is 
done apply the scratch brush. The subject will then have a 
burnished appearance. Afterward rub it with a felt wheel 
buff, or with the finger which has been dipped in wet, pow- 
dered pumicestone. This should be done on the chasing, 
so that the embossed surface will have a silvery appearance 
and the concave a black finish. The solution should be 
used on the day when made, and fresh solutions made as 
required, as it is of no use after twenty-four hours. 

Oxidizing (a Steel Color) Brass Articles 
without sllverplating. 

This is a process which almost any manufacturer may 
employ. It is economical and can be applied to a class of 
goods which find a ready sale in the market. In preparing 
this solution take two pints of muriatic acid and a hand- 
ful of filings or oxidized iron. The filings must be an- 
nealed, so that the acid will have the proper action. To 
the foregoing add one tablespoonful of arsenic acid and 
four times the quantity of water as there is muriatic acid. 
In using this solution articles should not be dipped into it 
until they have been cleaned. Should the articles be large 
use the scratch brush. This process is invariably success- 
ful, but it must be remembered that the solution ought 
always to be kept warm. It should be placed in a stone 



OXIDIZING COPPER. 61 

jar, within another vessel containing hot water, a bain- 
marie. 

Black Oxidizing for Bronze or Brass Articles. 

This formula is generally used in the manufacture of 

opticians' goods, such as opera glasses, telescopes, etc. 

It gives the black finish on the inside of these goods. 

The solution now employed in the large factories is as 

follows : 

One pound ammoniate of copper. 

One-half gallon ammonia. 

One-half gallon water. 

The solution given below is far better and more effec- 
tive than the former. It keeps the goods in a better state 
of preservation and will last much longer. 

Dissolve a silver dollar in nitric acid ; this will reduce 
the metal to what is called nitric silver. To this add half 
a pint of water. When the subject is taken from the bright 
dipping, dry it and warm thoroughly, and dip into the so- 
lution of nitric silver for a few seconds. Then place it in 
an oven and heat it until it turns black. Should it fail to 
come out with the black finish, immerse again in the 
solution of nitric silver. 

After the operation has been successful rub the subject 
with a piece of cloth and a little oil, and then dry once more 
in the oven. 

Oxidizing Copper. 

This is generally termed bronzing by electroplaters 
and is used for this kind of work in the large shops in 



62 THE PRACTICAL ELECTROPLATER. 

Paris ; for example, in oxidizing a statue. The object is 
first thickly copperplated. 

The following is the formula : 

One gallon of water. 

One-half ounce of sulphate of potash. 

One-quarter pint of ammonia. 

This mixture should be well heated, after which it will 
be ready for use. After the statue has been immersed take 
it out and apply a wet scratch brush until the surface as- 
sumes a dark cherry hue, which is a favorite color with 
art lovers. If the solution becomes weak, add ammonia 
and sulphate of potash until it becomes stronger. Should 
these two ingredients concentrate too much, they will eat 
the copperplating on the surface. 

The solution must be used on the same day it is 
prepared ; if it is not the bath will fail to do effective service; 
and should the plater have several days' work it must be 
compounded anew every day. This formula is very good 
for oxidizing badges and medals. 

Oxidizing Bronze Articles. 

The formula for oxidizing bronze and brass articles, 
especially for button factories, is in itself very simple, but, 
like everything else that requires judgment, it must be 
properly applied or the results will prove unsatisfactory. 
Formula for green oxidizing : 

Fifty pennyweights sugar of lead. 
One hundred and fifty pennyweights bi- 
sulphide of soda. 
One and a half gallons of water. 



OXIDIZING BRONZE ARTICLES. 63 

After the above ingredients have been thoroughly 
mixed put the mixture into a vessel or jar of iron enameled 
on the inside, and keep it as near the boiling point as may 
be possible. It is not absolutely necessary that the jar be 
enameled, but it is far more preferable, because the results 
obtained will be much more satisfactory than from an 
ordinary jar. Should the latter be used do not heat the 
solution over a fire. Take a vessel partly filled with hot 
water, place the jar containing the mixture in it, and then 
heat over an even fire or by steam, the latter course being 
better. At one time a kind of varnish was used in the 
various large button factories, instead of this solution, for 
the purpose of obtaining the necessary colors in finishing. 
Such a procedure seems absurd, and now that such marvel- 
ous strides have been made in chemistry it is no longer 
employed. The new process is much quicker in action, 
more economical, not so difficult, and the articles will have 
a finer finish. 

To illustrate, say there is a quantity of buttons to be 
oxidized. Place them in a dip basket the bottom and sides 
of which are pierced with small holes, as appears from the 
illustration on the next page. 

When taken out they will have a yellowish tint. If im- 
mersed a second time this tint changes to blue, and if a 
third time a greenish blue will appear. After this operation 
has been completed, take the basket out and rinse first in 
cold water and then in hot water. The buttons will then 
be ready for drying. Before being dried they must be 
thoroughly dripped and shaken until every drop of water 
has been removed. After drying place them in a brass wire 



64 THE PRACTICAL ELECTROPLATER. 

basket for a while, then take them out and throw them into 
a vessel containing transparent varnish. (See the formula 
for varnishing.) Afterward rinse in the solution prior to 
the final drying. The drying should be done in a moder- 
ately heated oven. 

This method is seldom used, because most people are 
not aware of its existence, and others do not realize its 




Dip Basket. 

value. A great many factories have not made use of it, 
because it was thought to be a waste of time. Such an 
impression is erroneous. It should always be used, and the 
author strongly recommends its employment by large button 
factories, particularly for the reason that the articles will 
have a brighter and more lasting finish. 

Lilac or Black Oxidizing. 

This is a method which is commonly used in button 
factories, especially in Stuttgart, Germany, and Waterbury, 



PROTECTION FROM ACIDS. 65 

Conn. Fancy buttons, such as are worn on ladies' gowns, 
hats and cloaks, form the bulk of the goods manufactured 
in those places. After the buttons have been taken from 
the bright dipping described elsewhere (see page 44), dip 
them in the following solution : 

One gallon of water. 

One quart of muriatic acid. 

Two ounces white antimony (or butter of). 

Be careful that the latter ingredient does not concen- 
trate, because if that occurs the buttons when taken from it 
will be black. This solution must always be used when 
near the boiling point, and in a dip jar. 



PROTECTION FROM ACIDS. 

Rubber gloves and rubber aprons will be found indis- 
pensable articles to those workmen who are called upon 




Rubber Glove. 



daily to do a great amount of dipping in strong acids. If 
the gloves are not used, the workman's hands will speedily 



66 



THE PRACTICAL ELECTROPLATER. 



become sore — a far from pleasant state of things. There 
is also the danger of blood poisoning, which will cause 
much suffering. It is therefore advisable not to incur any 
risk in this direction. The glove illustrated will be found 
a very useful article when the operator has to handle acid 
dipping and when oxidizing. 




SATIN FINISH, 



^=^HERE are many goods which it is impossible to 
QJ matt by means of acids, watch movements being 
i- an example. In these the acids will enlarge the 
holes. With the sandblasting apparatus (see Figure i) 
there is no risk of spoiling the goods or enlarging the holes ; 
as fine a matt as is desired may be obtained. If a fine matt 




Figure i — Positive Pressure Blower for Sandblasting. 

is wanted take fine sand ; if a thick matt, use coarse sand. 
Emery may be used for the same purpose. After the goods 



68 THE PRACTICAL ELECTROPLATER. 

have been matted and a frosted appearance is desired, 
brush them with a steel matting brush (see Figure 2). This 




Figure 2 — Swing Brush for Satin Finishing. 

may have the form of a swing brush or that of a scratch 
brush with steel wire. The author formerly manufactured 
his own swing brushes. It is not always possible to find in 
stock the exact thickness of steel wire necessary for the 
matting that is wanted. 

After the goods have been frosted pass them through 
potash to remove the grease, and then dip them in the 
solution given under the head of "Bronze Dipping." The 
goods should be entirely free of grease previous to doing so. 
Pass them through the acid rapidly, as there is danger of 
removing the frost finish if they are allowed to remain too 
long. A few seconds will be enough. Then rinse them 
in clean water and dip in the amalgamating solution, the 
formula for which will be found on page 32. 



DETECTION OF LEAD IN TIN. 69 

The goods should then be rinsed again in clean water 
and immersed in the dip gilding from ten to fifteen seconds. 
If the result obtained is not the desired one, and the goods 
have a spotted appearance, it is proof that the grease has 
not been thoroughly removed. This can be remedied by- 
means of a good, soft scratch brush with a high rate of 
speed, and by using a mixture of water and soaproots. 
Immerse once more in the gilding solution. 

If the articles are of gold or silver, it will be sufficient 
to pass them through the bath for removing the green (see 
page 20). This will remove the tarnish and grease. 



DETECTION OF LEAD IN TIN. 

In the tinning of copper and iron kitchen utensils, the 
nefarious practice indulged in by unscrupulous persons of 
substituting for pure block tin an alloy of tin and lead 
has been found dangerous to health, as lead is thus often 
conveyed into food and water in unsuspected ways, lead 
poisoning being the usual result. Tin foil used as a cover- 
ing for food comes under the same head. In addition to 
the suffering caused to the public it should not be forgot- 
ten that the industrial arts and honest tradesmen also suffer 
from the resultant suspicion cast upon all goods presumably 
lined with tin. The innocent, in fact, suffer for the guilty. 
It is therefore advisable to be acquainted with a simple and 
sure method of testing tin, or what passes for such. 

First- put a few drops of chemically pure nitric acid, 
about the size of a dime, on the tinning, and after the acid 



7o 



THE PRACTICAL ELECTROPLATER. 



has been expelled by heat let the tin become quite cold. 
Then let two drops of a solution consisting of a small tea- 
spoonful of iodide of potassium and 200 parts of water fall 
on the spot where the nitric acid was deposited. A bright 
yellow color, due to the formation of iodide of lead, will 
make its appearance, if lead is present. Minute quantities 
of lead may be detected by this simple process. 





VIEWS OF THE LARGEST PLATIN ; G PLANT IN THE WORLD. 



ALUMINUM ELECTROPLATING 
IN AMERICA. 




VERY effort has been made by the author to place 
before his readers any information that it was 
thought might be of service to them. With this 
idea there is presented an illustration of the biggest plating 
works in the world, engaged on the largest work ever 
undertaken. For the following description th.e author is 
indebted to the Scientific American : 

The tower surmounting the new City Hall of Phila.- 
delphia is 547 feet 3J4 inches high. A part of this height is 
stone and the remainder of cast iron with wrought iron 
bracing. 

Mr. MacArthur, the architect of the public buildings, 
fully appreciated the difficulty and expense involved in 
keeping the iron work painted and free from rust. It was 
estimated that it would cost $10,000 per annum. He pro- 
posed to make the outer skin of aluminum, but the high cost 
of that metal prevented its use, and the clock story, which 
is the beginning of the iron work, was cast in iron, and to 
preserve it from rusting it was intended to dip the different 
pieces in boiling linseed oil. When, on the death of Mr. 
MacArthur, Mr. John Ord succeeded him as architect, the 



72 THE PRACTICAL ELECTROPLATER. 

latter suggested that the iron work should be electroplated 
with aluminum to keep it from rusting, and after fully con- 
sidering the matter it was determined to first plate the iron 
with a thick coat of copper, which, by experience, it was 
known would protect iron, and then put a finishing coat of 
aluminum over the copper so as to make it harmonize with 
the rest of the tower, and prevent the copper from turning 
green and becoming unsightly. 

In the fall of 1891 at the works of the Tacony Iron and 
Metal Company, Tacony, Pa., which had the contract for 
the iron work of the tower, the construction of a building 
120 feet long by 60 feet wide was begun under the super- 
vision of the president of the company and was finished 
early in 1892. Mr. J. D. Darling of New York, had been 
appointed manager of the new plating works, and it was 
determined to use his process for plating with aluminum. 
By April, 1892, the huge tanks had been put in place, the 
electrical installation completed, and the different solutions 
to be used in plating made and run into the tanks. The 
plant was then ready to begin. 

The size of the largest castings determined that of the 
tanks. These were the columns and pilasters that surround 
the clock story. They are 26 feet long by 3 feet in diameter 
at the lower end. Therefore the tanks were made 28 feet 
long by 4 feet wide, by 5 feet deep, and hold about 3,800 
gallons when filled to the proper height. (The aluminum 
solution tank was made 8 feet deep for special work and 
holds 7,000 gallons.) The tanks rest in cement pits in two 
parallel rows of three each, as shown in the illustration, and 
when the solutions were run in water was admitted into the 



ALUMINUM ELECTROPLATING IN AMERICA. 73 

pits at the same time. The object of this was twofold — 
the water on the outside of the tank keeps it from leaking 
and also balances the hydrostatic pressure of the liquid 
within and prevents bulging. Over the centre of each row 
of tanks are I beams properly supported from the girders, 
and continuing for 30 feet outside of the building, on 
which run trolleys with differential hoisting blocks attached. 
To the two ends of the column or pilaster spiders with a 
central projecting trunnion are fitted by means of set.screws, 
and wrought iron slings with a bearing on one end are 
hooked to the tackle, and the end containing the brass bear- 
ing is passed over the trunnion. The column when hoisted 
is thus free to turn on its axis. The operation of plating a 
column is as follows : The column is placed on a truck 
resting on a narrow gauge track, of which there are two 
running into the plating shop. It is then run under the 
projecting I beam, and, the slings being adjusted, it is 
hoisted clear of the truck. By means of a windlass fastened 
to the side of the building and ropes running over guide 
pulleys, it is then pulled along the I beam over the first 
tank, which is of iron and contains a strong solution of 
caustic soda heated by a steam coil ; it is lowered in and 
boiled for several hours until all the grease and oil is dis- 
solved off. It is then raised and, after thorough washing 
with water from a hose, pulled over and lowered into the 
second tank and pickled with dilute sulphuric acid until all 
the rust and scale are dissolved and loosened. 

The column is then taken to the end of the building and 
thoroughly cleaned by the vigorous use of steel brushes 
and plenty of water. It then receives its first coat of 



74 THE PRACTICAL ELECTROPLATER. 

copper in the third tank, which contains a cyanide plating 
solution. When the metal is coated with copper it is 
removed from the bath, and any holes are soldered, the 
copper giving a good ground for the solder to adhere to. 
From there it is transferred to the second row of tanks and, 
after hav.ing been coated with paraffine wax inside, lowered 
into the fourth tank, which contains an ordinary acid cop- 
perplating solution. There it receives a heavy coat of 
copper (about 16 ounces to the square foot of surface) ; 
then, after having the paraffine boiled off, it enters the fifth 
or aluminum tank, and after receiving a heavy deposit of 
aluminum, 2 to 3 ounces to the square foot, is washed with 
pure water in the sixth tank and run out of the building and 
placed on a truck on the other track ready for removal. 
There are also two smaller tanks for plating small work, 
shown to the left in the illustration. The total amount of 
surface plated was about 100,000 square feet. The plating 
current was furnished by four dynamos, the largest of their 
kind ever built in the country for purely electroplating pur- 
poses, through copper conductors 6 inches wide by half an 
inch thick, which run underground and alongside the differ- 
ent tanks. These are insulated there with resin run in 
while melted. The dynamo shown to the left feeds the 
alkaline copper tank and develops 1,000 amperes at a pres- 
sure of 6 volts. The middle one develops 2,000 amperes at 
8 volts and furnishes current for the aluminum tanks. The 
two to the right are coupled together and develop 4,000 
amperes at 2% volts, which feeds the acid copper tanks. 

The columns and other pieces are brought into the 
electric circuit by wires passed around them like slings, 



ALUMINUM ELECTROPLATING IN AMERICA. 75 

and attached at the ends to a conducting brass bar over 
the tanks. 

In the cyanide tank a current density of 3 amperes to 
the square foot is employed ; in the acid tank 10 amperes, 
and in the aluminum tank 8 amperes. 

As it is often asserted that aluminum cannot be depos- 
ited from an aqueous solution, the following information fur- 
nished by Mr. Darling is of interest : Although aluminum 
is generally credited with indestructible qualities, and high 
resistance to corrosion, it has but few qualities that would 
make it advantageous as an electro-deposit upon other 
metals ; for while it resists atmospheric action when in a 
massive state, and retains a certain brightness for a long 
time, when it is deposited electrically from an aqueous solu- 
tion, which deposit is of necessity of a more or less porous 
nature, it soon tarnishes and assumes a dull bluish white 
color when exposed to the direct action of the elements. 
But for a protective coat, say for copper, for which purpose 
it is used on the tower, it answers very well, as the slight 
superficial oxidation that takes place protects the metal 
underneath from further attack, and the neutral color that 
it assumes harmonizes well with the stone work of the 
tower. 

For interior decorative work which is not exposed to 
atmospheric changes and can be protected by a coat of 
lacquer some very beautiful and lasting effects can be pro- 
duced by its use, as it can be finished with a fine matt 
or satin finish which is as white as that of silver. This 
finish may be produced directly in the bath. It is also 
easily polished. 



76 THE PRACTICAL ELECTROPLATER. 

Aluminum is, no doubt, more difficult to deposit than 
any other of the common metals. This is because of the 
high voltage necessary to decompose aqueous aluminum 
solutions, and its tendency to redissolve after being de- 
posited. The thermal data required to calculate the 
potential difference or electromotive force necessary to 
decompose the different aqueous solutions of aluminum 
were not in Mr. Darling's possession, but, reasoning by 
analogy, it must be several volts in each case, and as water 
requires only a minimum electromotive force of 1.5 volts 
to decompose it, at first glance it would seem that a com- 
pound which requires over 2 volts for its decomposition 
in aqueous solution would involve the decomposition of the 
water, and therefore would be impossible. But in reality 
this is not so, as may be seen in the case of caustic soda, 
which requires over 2 volts. Yet sodium may be ob- 
tained by its electrolysis if mercury be present to absorb 
it and protect it from the water. 

The fact is that when two substances are present re- 
quiring different E. M. F. to decompose them, if the E. M. 
F. is high enough to decompose the higher compound, the 
current is divided between them in some ratio decomposing 
them both, and Mr. Darling found that by using a solution 
of aluminum that had but a slight dissolving effect on 
aluminum, with a density of current of 8 amperes to the 
square foot, with sufficiently high voltage (6% to 7), alu- 
minum could be deposited on the cathode at the rate of one 
gram per hour per square foot, in a reguline state, and 
with higher currents it could be deposited much quicker, 
but was in a pulverulent state, which did not adhere. 



ELECTRO-METALLOCHROME. 






^HERE never has been a period like the present 
y in the art of metal coloring, and the demand for 
new and better processes than those now known 
is difficult to meet. Metal coloring has enjoyed much 
popular favor for more than half a century. In or about 
the year 1830 it received an extraordinary impetus in favor, 
owing to the introduction of the bronze coloring known 
as French bronze. This bronze color was invented by a 
Frenchman named Lafleur, who added one more feather to 
the cap of renown worn by France as evidence of what her 
sons have done and continue to do toward the advancement 
of every branch of art and industry. 

Since the year above mentioned this color and the 
varieties which have been produced from it have never 
failed to hold high positions in the esteem of the public and 
the trade. As a matter of course Lafleur's discovery led to 
the production of numerous other bronze colorings, which 
have likewise attracted much attention and secured a con- 
siderable share of favor. 

Nothing succeeds like success, and consequently one is 
not at all surprised to note the various steps toward further 
progress in this direction, particularly by the members of 
the trade in England. Working upon the ideas presented 



78 THE PRACTICAL ELECTROPLATER. 

by Lafleur's invention the English set about applying the 
bronze color upon artistic imitation bronze goods manu- 
factured out of cast zinc. This idea was speedily seized 
upon by the French workers, with the result naturally 
looked for ; that is, their sense of taste, always leading to 
refinement, quickly enabled them to apply the principles of 
metal coloring, electro-chemical and mechanical, to every 
description of metals and their alloys. With their natural 
superiority, which had become inherent as it were by genera- 
tions of artistic and technical training — which is a great 
point in any industry — they quickly became not only past 
masters in the art but authorities on it whose efficiency was 
conceded on every hand. One instance of how they set 
about improving, the process may be mentioned. They 
combined, and yet do so, the electro-chemical and mechani- 
cal methods for the purpose of producing different colors 
on one article, e. g., French bronze in conjunction with 
olive and antique greens. The groundwork is first made 
black or a dark color, and the parts that are prominent or 
embossed are gilded, silvered or oxidized in the colors that 
are desired. 

The metal coloring art is now very widespread in its 
applications, inasmuch as immense progress has been made 
by the French and English. However, the beauty and per- 
fection of finish of the artists of the early part of the nine- 
teenth century have not, it is safe to say, been surpassed by 
their successors in the same field of labor. 

While upon this subject it will not be inappropriate to 
reproduce the words of high praise uttered by Mr. Arthur 
H. Hiorns in his invaluable work, " Metal Coloring and 



FORMULAS FOR BRASS OXIDIZING. 79 

Bronzing " (Macmillan & Co., London and New York), 
published by him in 1892, a book up to date in every par- 
ticular and well worthy of perusal and study by those 
interested in the subject. The English are, as is well known, 
very serious in their utterances and usually mean what they 
say, and the extract is given as bearing out this assertion. 
The gifted author says : 

" The superiority of French workmanship is doubtless 
due to art and scientific training, the combination of theory 
and practice, so that while a change is taking place, or a 
particular solution is selected, the operative has an idea of 
the effect the desired color will have on the final result, and 
a knowledge of the chemical change requisite to produce 
that result. Every year adds to the sum of human knowl- 
edge with regard to chemical change, and therefore to the 
possibilities of an art which is so essentially a chemical one." 

There is more in the above extract from Mr. Hiorns's 
work than appears on a hurried perusal, and there is no 
hesitation in commending it to the notice of the worker who 
desires to acquire all possible proficiency in his chosen 
industry. There is no royal road to success, but there is 
one of incessant industry and research, and that is the only 
one that can be safely followed in this workaday world. 

Formulas for Brass Oxidizing. 

Several formulas are given herewith which will be 
found of much value to the workman. The first is for 
a greenish shade. This shade is obtained on brass objects 
by dipping them into a boiling solution composed of the 
ingredients mentioned below. The intensity of the color 



80 THE PRACTICAL ELECTROPLATER. 

obtained depends on the length of time the articles are left 
in the solution. The formula is : 

One gallon of water. 

One ounce sulphate of copper. 

Five pennyweights of hydrochlorate 
of ammonia. 

By the aid of the next solution the various shades of 
brown, ranging from orange brown to cinnamon, may be 
produced. Formula : 

One gallon of water. 

One and a half ounces chlorate of potash. 
One and a quarter ounces of sulphate of 
copper. 
To obtain a violet or a blue color the following solu- 
tion will be found effective : 

One gallon of water. 
One-half pound sulphate of copper. 
Three ounces hyposulphate of soda. 
One and a half ounces cream of tartar. 

If there are added to the foregoing 

Three ounces ammoniacal sulphate 

of iron and 
Three ounces hyposulphate of soda, 

there will be obtained, according to the length of time of 
immersion, yellow, orange, rose and blue shades. 

After a long immersion in the following solution a 
yellow brown color and then a remarkable fire red will 
be produced : 

One gallon of water. 

Three ounces chlorate of potash. 

Thirty pennyweights carbonate of nickel. 

Three ounces salt of nickel. 



FORMULAS FOR BRASS OXIDIZING. 81 

To obtain a beautiful dark brown color use the follow- 
ing solution : 

One gallon of water. 

Three ounces chlorate of potash, 
Two arid a half pounds salt of nickel. 

The subjoined solution will give several tints, starting 
with red, passing to blue and then to pale lilac : 

One gallon of water. 

Three ounces yellow sulphate of arsenic. 

Two and a half pounds of sal soda. 

The following will give a yellow brown : 

One gallon of water. 
Three ounces of salt of nickel. 
Four ounces chlorate of potash. 
Three ounces sulphate of copper. 

To obtain an iridescent color on brass use the follow- 
ing solutions, which must be prepared separately and then 
mixed : 

One gallon of water. 

Three ounces cream of tartar. 

Three ounces sulphate of copper. 

II. 
One-half gallon of water. 
Nine ounces of hyposulphate of soda. 

To obtain a very beautiful blue color on brass articles 
prepare the following mixture : 

One quart of water. 

Half an ounce concentrated solution of 
sulphydrate of ammonia. 



82 THE PRACTICAL ELECTROPLATER. 

The following will be found a good method of produc- 
ing a blue color on brass. The formula is as follows : 

One hundred and ten grams carbonate of copper. 
Eight hundred grams ammonia. 

Place this mixture in a wide mouthed glass bottle with 
a ground glass stopper. Shake until solution is effected. 
Then add 150 cubic centimetres of water and shake for a 
few minutes, when the solution will be ready for use. Keep 
in a cool place. The goods should be chemically clean and 
hung in the solution for ten minutes by means of a brass 
wire, and subjected to a to and fro motion, after which take 
them out and rinse in clean hot water and lay in sawdust. 




BADGE AND METAL OXIDIZING. 




^HE formula given below will work excellently on 
copper. Other metals may also be bronzed by 
this method, but they should first be copper- 
plated prior to dipping. The component parts are as 
follows : 

One gallon of water. 

Four ounces sulphate of potash. 

One teaspoonful of ammonia. 

This solution may be used for sterling silver or silver- 
plated work, but in that case it must be boiling and the 
articles must be scrupulously clean. They should also be 
scratch brushed after they have been taken from the dip- 
ping. For copper or plated goods the solution need only 
be slightly warm. To obtain a cherry color use a scratch 
brush for a long time — slowly, be it remembered — until the 
oxidation comes off and the desired color is obtained by 
the operator. With silver it is the reverse. That metal 
must be scratch brushed before and after dipping. When 
it has assumed a burnished steel color wet the hand and rub 
the surface of the article with pumice powder until the 
silver comes into view. 



84 the practical electroplater. 

Deep Black Color. 

On copper and copperplated articles, a deep black 
color may be obtained by means of the solution which is 
given herewith :• 

Seven pennyweights sulphate of barium. 

One quart of water. 

After the article has been immersed in the solution a 
light brown color is produced which gradually deepens till 
it assumes an intense black. The object must be rinsed in 
hot water and then allowed to dry. To secure a brilliant 
polish all that it is necessary to do is to rub it with chamois. 

Nobili's Rings. 

The method of producing the multicolored designs 
known as Nobili's rings was discovered by Nobili in the 
year 1826. A short description of the manner of producing 
them will prove of much interest. Take a shallow dish, 
such as is used by photographers, filled with a solution of 
sugar of lead, place a polished steel plate at the bottom of 
it, and connect by a wire to the positive pole of a two-cell 
Fuller battery or a dynamo, in which case regulate the 
current with the switchboard, the wire from the negative 
pole being attached to a disk of copper placed over the 
steel plate, but not close enough to be in contact. After a 
few moments the surface of the steel plate will have a 
beautiful prismatic appearance. The plate is then taken 
out and rinsed, which ends the operation. 

The same end may be obtained by another solution. 
Fill the dish with a solution of 

One ounce caustic soda. 

One-half pint of water. 



NOBILI'S RINGS. 85 

Dissolve this mixture and add thereto half an ounce of 
litharge. Boil the mixture for about an hour, let it settle ; 
decant it into the dish and add another half-pint of cold 
water. Place the steel plate at the bottom of the dish and 
attach to it the wire from the positive pole, which means 
reversing the poles. Then get a sheet of copper about the 
same size as the inside of the dish ; bend the sides over so 
that it does not touch the plate when placed in the dish, 
and connect the wire from the negative pole to the copper 
plate. As the current passes it causes the decomposition 
and deposition on the steel plate. As soon as the desired 
colors are obtained remove the steel plate immediately and 
wash it in clean water. On looking at it in a reflected 
light it will be found to possess all the prismatic hues. 
This is owing to the peroxide of lead being deposited im- 
perfectly — that is, in various thicknesses. 

If the plate is allowed to remain in the solution after 
the tint wanted has been secured the colors will be lost 
and it will appear a dull colored yellow or brown. If 
the current is too intense the same effect will result. 
Care must be taken that it should not exceed 3 volts and 5 
amperes. 

Various articles, such as bells, dials, watch and clock 
hands, or picture frames, may be successfully treated by 
means of this process. The subject must be gilded or 
nickel plated beforehand, when very beautiful colors will 
be obtained. Different designs may be produced upon the 
articles by twisting a piece of thin copper wire into a spiral 
or a square form, or by making a cross of thin sheet copper 
the colors will radiate on the article beneath. 



86 the practical electroplater. 

Black Color on Brass. 
A formula for black coloring is "given on another 
page. The following solution is for use on brass directly : 

One-half pound of sulphate of copper. 
One quart of water. 

Dissolve the sulphate of copper in water and then add 
enough ammonia to redissolve the sediment which first 
forms. This solution must be used hot to obtain an ad- 
herent color on the articles. 

Brown Color or Bronze Barbedienne. 

By this method brass articles can be colored brown. 
Brassed zinc and iron articles take on brownish black 
shades, which nevertheless are beautiful. The solution is 

Three parts red sulphide of antimony. 
One part finely powdered red iron oxide. 

Triturate the mixture with sulphide of ammonia so as 
to make a thin paste. Apply the paste by means of a 
brush. After drying it in a warm place remove the powder 
with a soft brush. 




THE GALVANOMETER. 



ANY electroplaters, particularly those possess- 
ing but slight scientific knowledge, or none 
i cAj IjjL. at all, and who work by instinct, as it were, 
turn out good work without the aid of any instrument for 
detecting electricity or ascertaining its strength. It is not 
uncommon to see platers trying to ascertain the strength 
of a current by putting the ends of the wires at the sides of 
the end of the tongue. Another means of testing is by the 
spark passing between the ends of the wires when they are 
separated, and yet another is by running one end upon a 
file to which the other has been attached. The last two 
methods are very deceptive and are only uncertain guides 
with a certain length of wire, as long wires emit much 
larger sparks than short wires, particularly if they are 
wound spirally. 

To detect the presence of electricity it is preferable to 
use a simple galvanometer, as it will indicate to a certain 
extent not only the strength of the current but its direc- 
tion. The galvanometer is used for various purposes by 
platers, testing the strength of new cells, for instance, or 
for detecting a short circuit, or the reversibility of polariza- 
tion, or the amount of current used by some baths. A 
good instrument should be finely balanced on an agate or 



88 THE PRACTICAL ELECTROPLATER. 

ruby centre, and provided with an accurate graduated card. 
Such instruments will be found of great value to the elec- 
troplater. There is given herewith an illustration of a 
pocket galvanometer. 




Pocket Battery Gauge. 

Besides galvanometers there are voltmeters and am- 
peremeters, which are used only for experimental purposes 
and for testing dynamos and motors. There is but little 
use for them in ordinary plating rooms, however, and it is 
better to procure their use than to buy them. 



BUYING A DYNAMO. 






^r^HERE should be as much ability shown in pur- 



y chasing a dynamo as in any other transaction 
in everyday life. This is mentioned because 
it is a regrettable fact that many constructors of electric 
machines take advantage of the want of knowledge dis- 
played by would-be purchasers of machinery. Perhaps 
t-hey do not themselves possess the necessary knowledge 
of the subject but ; they should. The seller will tell a 
prospective customer that he has a machine in his posses- 
sion that will do the plating for so many square feet, 
although such may not be the case. Consequently the 
buyer has only his own judgment to depend upon in this 
very important matter. The proceeding is very wrong of 
course, but it is quite often done. 

When a person finds that it is necessary for his busi- 
ness to have a new dynamo, the first step he takes is 
to examine the construction of the one offered for his 
approval, for the purpose of ascertaining its advantages 
for his purposes. Such a machine should have a slow speed 
and yet at the same time produce as much current as is 
possible, because a high rate of speed will quickly wear 
out the bearings by causing too much vibration and heat- 
ing the armatures. This is harmful to the insulation of the 



9 o THE PRACTICAL ELECTROPLATER. 

wires. A lengthy description of the dynamo used by the 
author of this work will be found at page n. From it ioo 
amperes and 10 volts are obtained. A dynamo of this de- 
scription is to be had at a cost ranging from $100 to $150, 




Brunor's Perfected Dynamo. 

and with its aid from 10 to 20 square feet can be plated. 
It is only by means of a galvanometer that the amperes 
and volts of a machine can be controlled — that is by the 
amperemeter and voltmeter. (See illustration.) 



FORMULAS FOR BRITANNIA 
METAL. 




Casting Britannia (or White) Metal. 

^-^Ifs^HE formula for casting britannia metal, or, in 
other words, soldering metal, will be found 
below. It is of very great service to workers 

in britannia metal, and is as follows : 

Two parts of tin. 
One part of lead. 

Two pounds of antimony per hundred 
of soldering metal. 

As a rule it will be found that after the metal has been 
mixed according to the foregoing formula it will not flow 
freely. To avoid this annoying experience a method is 
given whereby the metal will run perfectly clear. After the 
tin has been melted put the antimony in and stir well in 
order that it may mix well with the tin. Then put in the 
one part of lead, and when that has been well melted take 
a spoonful of the composition, run it on a level iron plate, 
and let it cool. If the metal comes out in a porous con- 
dition it is a sure sign that there is too much lead present. 
If the assay appears with a " sinkage " it will be necessary 
to add a little more lead. The best way to proceed is to 



92 THE PRACTICAL ELECTROPLATER. 

take a small quantity in a spoon, drop a little lead into it, 
and run the assay on the iron plate, as previously mentioned. 
If after this has been done it presents a clear and bright 
surface the metal is ready for casting. Sometimes it is the 
fault of the mold, if the latter has not been sufficiently 
heated. If the metal is too hot it will cause " sinkages," 
as the term is popularly used in the trade. On the other 
hand, if the mold is not warm enough the metal will fail to 
run all over. The whole process depends on the skill of 
the workman. 

A new mold should be well heated on the fire, and its 
surface rubbed with nitric acid by means of a piece of 
wood. After this has been done place it on the fire again 
and warm it until its surface becomes black. Then dis- 
solve a small quantity of polishing rouge in water and rub 
the surface of the mold with it with a pencil until the 
former becomes of a red hue. The mold will then be ready 
for casting, provided of course that the metal is at a proper 
degree of heat. Recollect that the metal should never be 
run while in a red hot condition. 

Mixing Black Metal. 

The formula for mixing black metal is as here given : 

One hundred pounds of lead. 
Thirteen pounds of antimony. 

Run out an assay on an iron plate from this formula, 
in order to ascertain the quality of the metal. The point to 
be noted is whether the surface of the assay is of a bright 
appearance. If it is not, and if it is of a dull hue, with 
white spots present, add thereto clear tin or mixed white 



CASTING WHITE METAL. 93 

metal until it becomes perfectly clear. The metal will then 
be ready for casting. 

White Metal (Britannia) Alloy. 

The formula for this alloy is as follows. The rolled 
metal alloy is first given : 

One hundred pounds of tin. 
Eight pounds of antimony. 
Two pounds of raw copper, or 
Four pounds of copper and tin. 

To prepare copper for britannia metal smelt in a 
crucible 100 pounds of copper and a like quantity of tin, 
and put the result into ingot shape. When needed take 
an amount of equal proportions as given in the above 
formula. Attention is particularly drawn to this, inasmuch 
as it is very difficult to smelt copper in the tin kettle. It 
is necessarv to smelt it in the crucible. Afterward add 
the tin gradually to the copper in the crucible. When the 
ingot has been manufactured pieces can be broken off 
easily, as desired. 

Casting White Metal. 
For hard white metal the ingredients are as follows : 

One hundred pounds of tin. 

One and a half pounds of raw copper, or 

Three pounds of copper and tin. 

Ten pounds of antimony. 

Melt the copper in a crucible and then drop it grad- 
ually into the melted tin in the kettle. 



94 the practical electroplater. 

Soft Cast Metal. 
The ingredients for this substance are as follows : 

One hundred pounds of tin. 
Five pounds of antimony. 
Three-quarters of a pound of copper. 

The instructions for this are the same as given on 
page 93 for casting white metal. 

Soft Solder. 

The component parts of this composition are well 
known, but it has been thought desirable to reproduce 
them here. They are as follows : 

Two pounds of tin. 
One pound of lead. 

Do not forget to cast the copper in the crucible first, 
and then add the tin. 

Medium Solder. 

The formula for this solder is as here given : 

Two pounds of tin. 
One pound of lead. 

To the above add tin until the solder presents a 
speckled appearance — that is, with white spots throughout 
the metal. When this appearance has been obtained the 
workman is assured that the metal is ready to be used. 



BRASS PLATING. 



w& 



ZS^Z^T^ITHIN the past ten or fifteen years working 
in zinc or imitation bronze has received 
an immense impetus, especially among the 
Parisians, who imitate works of art, &c, in zinc and brass 
plating and oxidize them with such rare skill that they are 
quite often mistaken for real bronze ware. Some of the 
Parisian manufacturers turn out very fine specimens of 
work in this branch of the trade, especially Blot & Drou- 
ard. This firm devotes its energies particularly to repro- 
ducing ancient works of art and has produced very fine 
specimens of the Venus de Milo and other noted master- 
pieces. Workmen who spend any length of time in this 
factory learn very much that is of value to them. The 
noted Pere Adolphe, who is reckoned the best brass plater 
in Paris, has been with the firm since it started, over thirty 
years ago. Indeed he has been one of the props of the 
establishment, which is giving him scant praise. 

In the United States at the present time the art of 
working in cast iron (which replaces zinc for many articles) 
has reached that stage of progress which may be safely 
said to have surpassed the workmanship of the Parisians — a 
result that has only been arrived at by incessant labor and 
improved taste. Very fine specimens of fancy work in iron 



96 THE PRACTICAL ELECTROPLATER. 

i are put on the market, and the only rivals that Americans 
now have in this industry are the English. As a matter of 
fact it is well known that the English workmen in cast iron 
who come to the United States receive very high wages — 
higher even by far than the salaries paid to their American 
confreres, another indisputable instance of the value placed 
upon skill. 

We here give a full description of the practical opera- 
tion of brass plating : 

Brass plating is not at all like gold and silver plating. 
The method of manipulation is quite different and much 
more difficult, because two different metals that are united, 
copper and zinc, have to be dealt with. We will demon- 
strate the difficulty that an operator has to overcome to 
arrive at a satisfactory result. For instance, take a quan- 
tity of sulphate of copper and dissolve it in water. When 
the crystals have been dissolved add carbonate of soda 
until the copper settles at the bottom. Do not put too 
much carbonate in at once, for if that is done there will 
be an undesirable effervescence. 

When the copper has settled throw the water away 
and wash the sediment, technically termed carbonate of 
copper, three or four times, until the acid and the carbonate 
have disappeared, leaving only the carbonate of copper. 
Every time the sediment is washed let it settle. The same 
method is pursued with sulphate of zinc. When the car- 
bonates of zinc and copper have been obtained, take two 
parts of copper and one part of zinc. It is of course un- 
derstood that large quantities are spoken of and that it is 
more advantageous for a plater to prepare the carbonate of 



BRASS PLATING. 97 

copper himself, as he will find it to be much cheaper. For 
every pound of copper take a pint of ammonia, when an 
azure hue will be obtained, known in the trade as copper of 
ammonia. Then add cyanide of potassium until the copper 
and zinc are dissolved. A yellow color will then have been 
obtained. For every pound of copper and zinc add from 
four to eight gallons of water ; for every four gallons 
of water add one pennyweight of arsenious acid. The 
latter is added for the purpose of giving a bright tone 
to the plating. Then add cyanide of potassium until from 
8° to io° Baume hydrometer has been arrived at. It is a 
rule in electroplating that 20 must never be passed. For 
every pound of carbonate of copper and carbonate of zinc 
add four pounds of carbonate of soda. 

Theory is very good in its way, but practice is by far 
the most important point. After the bath has been pre- 
pared put in two plates and connect them with the positive 
and negative poles. Let the current run from two to three 
hours, until the bath has been electrolyzed. This operation 
is not only suitable for a new brass bath, but will be found 
serviceable whenever the bath does not work well. The 
bath must be lined throughout with brass anodes and the 
cathode must be about 4 inches from the anode. The 
bigger the bath and the more objects there are in it the 
better the results. It is very hard to work regularly with a 
small bath. This solution can be used for any metal and 
in large quantities, and will be found invaluable to electro- 
platers. 

To keep the bath in good condition dissolve with 
cyanide of potassium, say on the last working day of the 



9 8 THE PRACTICAL ELECTROPLATER. 

week, carbonate of copper and ammonia. This will enrich 
the bath. The bath should work with a current propor- 
tionate to the cathode. Every square foot of cathode 
means merchandise. From 10 to 15 amperes will be needed, 
which will be dependent on the operator. 

If the operator prepares a bath too rich in zinc a weak 
current will be needed, which means from 8 to 10 amperes 
to a square foot. If, on the contrary, the bath is rich in 
copper, then from 10 to 15 amperes will be found necessary. 
For copperplating, however, to produce a nice coating 
and an equally nice tone, 5 amperes will be found to be 
enough for every square foot. If the goods are taken 
from the brass plating with an earthen or dull matt hue 
it is proof positive that there was not sufficient arsenic 
put in when preparing it. On the other hand, an excess 
of arsenic is irremediable, for the articles will be found 
to have a whitish appearance and the bath will be in- 
active. Trimming, like screws, nails, &c, must be put into 
a wire basket. It must always be borne in mind that if 
zinc work be prepared it should be passed through potash 
and then through the pickle, as mentioned elsewhere. 
Iron hooks should be used always. Hooks of brass or 
copper should not be dipped in the sulphuric acid pick- 
ling, for if they are a little of the copper metal, we will 
say, will be eaten away. This will impart a reddish color 
to the zinc and consequently prevent the adherence of the 
brass plating. 

Every bath should have a switchboard, so that the 
current may be regulated as desired. 



ELECTROPLATING PLANT. 




^HE illustration herewith given is reproduced for 
the purpose of giving the operator an idea how 
to place his plant so that operations may be 
performed without unnecessary trouble or difficulty. The 
operation of plating is clearly shown. The illustration 
exhibits the position of the anode and cathode and that of 
the battery and the bath. The centre or positive plate of 




Electroplating Plant. 



the battery is connected to a rod running across the trough. 
To the positive plate are suspended the anodes, a, a, a, of 
gold, silver or copper, or any other metal that it is desired 
to obtain a deposit from. The plates of the battery, or the 
negative elements, are attached to the other rod across the 
trough, and to this rod the articles that are to be plated are 
suspended, as shown at b y b, b. A clear idea may be ob- 



ioo THE PRACTICAL ELECTROPLATER. 

tained by a careful study of the illustration. For instance, 
the workman may desire to do silver plating. He prepares 
his silver solution as given under the head of " Silver- 
plating " (page 53), and treats the goods as spoken of under 
"General Rules for Electroplating" (page 125). The 
battery illustrated or any other battery may be used, Bun- 
sen, carbon, Smee or Bunnell. The distance of the battery 
from the bath does not matter ; they need not be near each 
other. The wire may be run from the battery to any de- 
sired distance. The connecting wires must be insulated. 
The bath containing the solution may be of glass or an 
enameled vessel, or may be of wood lined with pitch. In 
electroplating shops wooden tanks are generally used for 
the silver solution, and for the gold solution iron enameled 
pots or porcelain evaporators. 




NICKEL OR SILVER PLATING 
BATTERIES. 



The Bunsen Battery. 

""lo NQUIRY has often been made of the author as to 
X? what, in his opinion, is the best kind of battery for 
xl plating. It would be an invidious task to discriminate 
between the different makes of batteries, and bearing this in 
mind it was determined to give descriptions of the various 
batteries in everyday use. As the Bunsen holds a well 
recognized position in the estimation of experienced platers 
a description of it is given. The Bunsen is a modification of 
Grove's. It is much used on the European continent for 
electrical purposes. Platinum is used instead of carbon, and 
for convenience it is usually cylindrical in form. The 
method of construction is to form a hollow cylinder by coking 
pounded coal in an iron or bronze mold. The coke used in 
this cylinder is taken from the residue left in the gas retorts. 
The coke cylinder is then soaked in a solution of sugar and 
calcined a second time. This gives great compactness. 
The porous cell holding the zinc and dilute acid is placed 
in the cylinder and the whole put into a glass or stone- 
ware vessel charged with nitric acid. The coke cylinder 



102 THE PRACTICAL ELECTROPLATER. 

and the zinc are of course connected, and thus the battery 
is completed. Nitrous fumes are evolved from the Bunsen 
and are very unhealthful. The author recommends that 
these batteries be placed out of doors or else in a strong 
draught. 

A much simpler and far less expensive modification of 
the foregoing arrangement is to put a solid bar of carbon or 
of coke into a porous cell that has been filled with nitric 
acid, which is placed in a stone or glass jar filled with 




Bunsen Battery. 

dilute sulphuric acid, having a cylinder of zinc around the 
porous cell, leaving a space of about an inch between the 
porous cell and the zinc, and using carbon instead of plati- 
num. The improved Bunsen cell (see illustration) is of 
great power for nickel and silver plating, and for the pur- 
pose of running electro-motors, &c. One hundred gallons 
of nickel solution have been used successfully with two of 
these cells. The glass jars contain six quarts, and form a 
convenient tank for experimental work. 



THE SMEE BATTERY. 103 

In setting up the nickel plating battery take care to 
amalgamate the zinc thoroughly inside and out. Into each 
of the porous cups put two ounces of nitric acid, and half fill 
the cup with a mixture of equal parts, by measure, of water 
and sulphuric acid. Then place the carbon in the porous 
cup and add the mixture of water and sulphuric acid until 
the proper height is reached. Put the zinc in the outer or 
glass jar, and fill to the top of the zinc with a mixture of 
one part of sulphuric acid to twelve parts of water, which 
has been mixed beforehand and allowed to cool. The fluids 
in the porous cup and the outer jar should be of the same 
height. When the liquid in the jar becomes milky it is 
necessary to replace it with a fresh solution. A small 
quantity of nitric acid should be occasionally added to the 
liquid in the porous cells, and the zinc should be well 
amalgamated. Nitric acid of a strength of 40 , clear, or 
which has been saturated with bichromate of potash, will 
increase the intensity of the battery. 

The Smee Battery. 
A few defects in the ordinary zinc and copper battery 
were considerably lessened by a very ingenious contrivance 
of Alfred Smee, who had noticed that if the copper plate of 
the battery be roughened by the action of corrosive acids 
or by rubbing the surface with sandpaper its action was 
made considerably more efficient, as the roughened surface 
evolved the hydrogen far more freely. Taking advantage 
of this principle he coated platinum foil with a finely divided 
black powder of platinum, deposited from a solution of 
that metal by means of electricity, and used this in place of 



104 THE PRACTICAL ELECTROPLATER. 

the copper in the common battery. Smee afterward made 
use of silver foil, which is much cheaper, in place of plati- 
num foil. The method of preparing these plates is given 
by Smee as follows : 

" The silver to be prepared for this should be of a 
thickness sufficient to carry the current of electricity, and 
should be roughened by brushing it over with a little strong 
acid, so that a frosted appearance is obtained. It is then 
washed and placed in a vessel with dilute sulphuric acid, to 
which a few drops of nitro-muriate of platinum have been 
added. A porous tube is then placed into this vessel, with 
a few drops of dilute sulphuric acid ; into this tube a piece 
of zinc is put, contact being made between the zinc and 




Smee Battery. 

silver ; the platinum will in a few seconds be thrown down 
upon the silver as a black metallic powder. The operation 
is now completed and the platinized silver is ready for use." 
A simple method, obviating the use of a battery, is as 
follows : Lay the silver between two pieces of sandpaper, 
press it with an ordinary smoothing iron, and then pull the 



THE SMEE BATTERY. 



105 



silver out while under the pressure. The platinum solution 
is made very hot and the silver dipped in it for some time, 




The Grenet Battery. 



which effects the coating. The nitro-muriate of platinum 
is easily prepared. Take one part of nitric acid and two 



106 THE PRACTICAL ELECTROPLATER. 

parts of hydrochloric acid (muriatic acid). Mix together 
and add a little platinum, either as metal or sponge. 
Keep the whole at or near a boiling heat. The metal is 
then dissolved, forming the solution required. 

The illustration on page 104 is that of a Smee battery, 
representing a single cell of this form, s is the platinized 
silver plate, z, z the two amalgamated zinc plates, and w 
the crossbar. As it is essential to the proper working of 
the battery that the plates be always parallel to each other, 
the wooden frame is usually extended around the edge of 
the thin silver plate, though it is not so represented in the 
illustration. One of the clamps at the top of the wooden 
bar is joined to the platinized silver plate, and the other to 
the pair of zinc plates, in place of a glass or stoneware jar. 
Small troughs, square in form and made of gutta percha, 
are often used for this sort of battery. They suit admirably 
and are not liable to be broken. 

The illustration on page 105 shows the American form 
of the Grenet battery, which consists of two plates of car- 
bon, with zinc between them, the zinc bar being placed in 
the middle so that it can be moved up and down. When 
the current is no longer wanted the zinc can be raised, thus 
stopping the operation. This battery is good only for a 
short time and for small jobs, such as the joint of a chain 
or for a scarf pin, or for recoloring a ring. 



WATCH CASE GILDING. 




k HE gilding of watch cases is now a very im- 
portant industry in the United States, and the 
problem confronting gilders is how to do it as 
cheaply as possible, at the same time turning out work 
which will be satisfactory in every way. With this purpose 
in view the author herewith devotes a chapter upon the 
preparation of the articles prior to gilding, which is the 
chief essential to a successful outcome of the operation. 

The case must first be carefully polished and then 
dipped into a solution of boiling water, soap and carbonate 
of soda. Let the case remain in the solution from one to 
two minutes. Then rinse it in boiling water, after which 
dip again in a solution of caustic soda of a strength of from 
5° to io° Baume. Rinse once more in cold water. 

Copper and brass and their alloys will of course be- 
come tarnished during the foregoing operation. In order, 
therefore, to remove the tarnish it will be necessary to dip 
the article in a solution of cyanide of potassium and water 
of a strength of from 2 to 5 Baume. The case must not 
be immersed any longer than two or three seconds, because 
the cyanide of potassium is liable to spoil the high polish 
of the case. The case should then be rinsed once more. 
It is not necessary that the cyanide solution should be 
warm. It must be cold. After this the case will be ready 



108 THE PRACTICAL ELECTROPLATER. 

for gilding by means of the formula given below. First 
dissolve in an evaporating dish 

One ounce fine gold, 

Two parts muriatic acid, c. p., 

One part nitric acid (aqua regia), c. p., 

applying gentle heat to accelerate chemical action. When 
the gold is all dissolved heat the mixture until all the acid 
is evaporated. A red mass will be the result. It is advis- 
able when the acid is nearly expelled to turn the dish all 
around, so that the liquid may be dispersed over a large 
surface of the vessel. It will be found that the liquid will 
cease to flow when the acid is expelled, at which period the 
operation is finished. If too much heat is applied the gold 
will return to the metallic state, which may be known by 
the red mass acquiring first a yellow tinge, and next a gold 
bronze will be observed at the bottom of the dish. In 
such a case it will be necessary to add a little more aqua 
regia in the same proportion as before, which will at once 
redissolve the metallic gold. When the acid has evapo- 
rated from the chloride of gold add about a pint of water, 
which will at once dissolve the chloride, forming a limpid, 
straw colored solution. 

To the foregoing formula must be added from one to 
three gallons of water, 10 ounces of cyanide of potassium 
and 5 ounces of carbonate of soda. 

The formula for the copper solution to be mixed with 
gold is as follows : 

Ten pennyweights of carbonate of copper. 
One teaspoonful of ammonia. 
One ounce cyanide of potassium. 



PRACTICAL HINTS ON GILDING. 109 

Put the carbonate of copper into half a pint of water 
and add a teaspoonful of ammonia until it is of a thor- 
oughly dark blue color. Then add the cyanide, which will 
impart a clear yellow color. Pour the mixture into the 
gilding solution and boil for about an hour before using, in 
order that it may mix well. 

The gilding solution may be made with over a gallon 
of water and may be increased to three gallons to one 
ounce of gold, but an additional four ounces of cyanide of 
potassium must be added for every extra gallon. As the 
gold solution evaporates by reason of its being heated, the 
water used in rinsing the article after it is taken from the 
bath must be used so as to bring the solution to its original 
level and to prevent waste of gold. It is of course under- 
stood that it is one of the rules in electroplating that the 
solution must be over 5 and not above 2o Q Baume. The 
anode must be of 14 karat gold, alloyed with silver and 
copper. The shade desired is dependent on the taste of 
the operator. By exposing a large surface of anode in the 
solution a red color is obtained. If the point only of the 
anode is dipped a yellow color is obtained. This yellow 
shade is used for cases of low karat gold. 

Practical Hints on Gilding. 

According to the amount of gold deposited so will be 
the durability. A few grains of gold will serve to produce 
a gold color over a very large surface, but the coloring will 
not be permanent. This shows that it may be used for the 
most inferior quality of gilding. For example, a watch 
case may be gilded at a minimum cost of fifteen cents, but, 



no THE PRACTICAL ELECTROPLATER. 

on the other hand, a heavily plated case should have a 
coating ranging from 20 grains to a pennyweight. A slight 
coloring will be sufficient for the inside, but the outside 
should be heavily coated. In order to do this the case is 
opened inside and out, and is closed in a bowl of water so 
that it may be filled with the fluid. Then apply the heavy 
coating. After this is done open it and gild lightly inside. 
A watch case thus gilded will, with ordinary wear, last five 
or six years without requiring regilding. 




DOUBLE SPEED ALARM 
INDICATOR. 




^HIS is the age of invention. The nineteenth cen- 
tury has proved more prolific in valuable in- 
ventions than any other preceding hundred 
years, and its last quarter has surpassed the previous three. 
Patent claims by the thousand are entered at the Patent 
Office in Washington yearly, of which few are heard of 
afterward. This is merely the survival of the fittest. 

It is the author's purpose to introduce here to the 
notice of the reader, on account of its merits solely, the 
double speed alarm indicator of Weiss Brothers. It is in 
use in the author's factory, and fully deserves mention for its 
value. It is needless to say that on the speed of machines 
the success of manufacturing greatly depends. The speed 
indicator has met with considerable favor, based entirely on 
its merits, wherever it has been adopted. It possesses many 
advantages, which, it is generally conceded, have secured 
for it the high estimation in which it is now held in those 
workshops using it. 

By the aid of this invention the number of revolutions 
of a shaft, turning either to the right or to the left, can be 



ii2 THE PRACTICAL ELECTROPLATER. 

determined much more accurately, quickly and easily than 
by any other instrument at present in the field. It will be 
admitted consequently that it is of considerable value. Its 
advantages may be summed up as follows : 

i. It is always in the correct position to be attached to 
the shaft. It requires no turning to zero. Once in position 



Weiss' s Double Speed Alarm Indicator. 

it requires no further attention, and it is immaterial whether 
the spindle turns to the right or to the left. 

2. The friction caused by the pressure against the 
shaft is reduced to a minimum by the use of a hardened 
stub steel socket, in which the hardened spindle of the same 
material rests and turns. 

3. It relieves the eye of half its work by the use of a 
bell, which constitutes its distinctive merit. The bell rings 
at every hundred revolutions of the spindle. In place of 
working from a timepiece to the indicator, and vice versa, 
the workman keeps his attention solely on the timepiece 



PREVENTING RUST ON STEEL. 113 

while he notes the successive hundreds. When the test is 
concluded he closes his watch, glances at the hands of the 
indicator, which registers the odd revolutions, adds them to 
the hundreds already tallied, and the work is ended. 

It will thus be noted that everything is quite simple. 
There is no confusion or worry, no divided attention, and 
no mental strain — advantages of considerable value. The 
operator watches the seconds hand of his watch, and the 
bell " does the rest." 

In addition to these advantages there are others, namely, 
the smallness and lightness of the indicator, and its con- 
venience (it may be carried in a vest pocket). 



PREVENTING RUST ON POLISHED STEEL. 

The appearance of rust on steel is always a source of 
annoyance to those who desire to have everything of a 
spick and span appearance. Numerous methods of doing 
away with rust are known, but that here given will prove 
very serviceable. Fill a glass funnel with calcium chloride 
and place it in a jar in the room or other place where the 
steel ware is deposited, such as showcases in cutlery and 
other stores. 

It will be found that all traces of moisture are quickly 
absorbed by this simple arrangement. 

The arrangement of the funnel and jar allows the 
liquefied portion of the calcium chloride to trickle from the 
former into the latter drop by drop. The salts are left ex- 



ii 4 THE PRACTICAL ELECTROPLATER. 

posed, so that the calcium chloride continues to act until 
entirely dissolved. 

It will be observed that the plan outlined in the fore- 
going paragraphs is very simple, and at the same time it 
will prove to be one of the most advantageous to store- 
keepers who keep large quantities of steel goods on hand. 
Its simplicity commends it to every person who has used 
it or who will try it, and its cost is comparatively trifling. 
Ideas of this sort should be within the knowledge of all 
who experience annoyance from rust on their goods, annoy- 
ance which never need be felt if some such plan as given 
here is adopted in their stores. Too often dilatoriness in 
applying a simple idea like that under discussion is the 
cause of much bother in seeking to cleanse goods of rust. 




EFFECTS OF CYANOGEN ON 
HEALTH. 



"Tq T is to be hoped that the recital of the effects of cyan- 
X ogen on the health will not deter anyone from pur- 
^1 suing the electroplating trade. Carefulness and 
regularity in living are essential to the well-being of indi- 
viduals in most branches of industry, and in none more so 
than in electroplating. The author knows a workman who 
has worked at the trade for forty years and yet enjoys 
good health, the consequence of the care taken of himself 
— a case of a sound mind in a sound body. 

The effects upon the health of those who work steadily 
over cyanic solutions are well known. The author's experi- 
ence is similar to that of other electroplaters, and conse- 
quently he must warn those in the business, or those who 
may in any way come in contact with cyanide solutions, to 
be extremely careful and not to use too much freedom. The 
hands of gilders and platers are subject to ulceration, es- 
pecially if they have been dipped in a solution. These 
ulcers are painful and annoying. On first appearing, if not 
properly washed in strong cyanide of potassium and after- 
ward in acid water (the latter for the purpose of destroying 
the cyanide), the workman will have to take a rest of a few 



n6 THE PRACTICAL ELECTROPLATER. 

days very quickly. If the flesh near the sores is pressed to 
a point by squeezing, water will issue from them. This 
assuages the pain. Eruptions appear on a workman's body 
sometimes after inhaling the fumes if the latter have been 
very bad, as frequently occurs when solutions are evap- 
orated to dryness or precipitated by acids in a close room 
for the recovery of the metal. The legs of workmen are 
frequently seen thus afflicted, and always after they have 
been exposed to the effects of extra strong fumes. 

The following resume of the general effects of electro- 
plating and gilding on the health as experienced by the 
author will prove interesting": 

The gas has a heavy, sickening odor ; in the mouth 
there is a taste as of bitter almonds and a scarcity of saliva, 
and whatever there may be of the latter is frothy. The nose 
becomes dry and itchy and minute pimples are to be found 
within the nostrils. These pimples are very painful. These 
effects have also been experienced in the nose from the 
hydrogen of the batteries, where there were no cyanide 
solutions. There is also a general condition of bodily lan- 
guor, in addition to a disinclination to take food and an ab- 
sence of relish. After this state of things has lasted some 
time a benumbing sensation in the head is felt, with pains, 
which are not acute, darting along the brow. The head 
feels as if it were a heavy mass, without any individuality 
in its workings, as if it had been severely wrenched and as 
if there were a headache. Sometimes there is bleeding from 
the nose in the morning when fresh from bed, and after that 
comes giddiness. Objects are seen flitting before the eyes 
and there are momentary feelings as if the ground were 



EFFECTS OF CYANOGEN ON HEALTH. 



117 



rising and then leaving the feet, so as to cause staggering. 
Feelings of terror, gloomy apprehension and irritability of 
temper, sometimes approaching madness, follow. A rush 
of blood to the head ensues, which is felt behind the ears, 




La Rue Electric Fan. 



with a kind of hissing noise, and causing blindness and 
pain. This will pass off in a few seconds, but a giddiness 
will remain which will last for a few minutes. When this 
stage has been reached all attempts to work should cease 
for a few days. Recovery will then set in and there will 



n8 THE PRACTICAL ELECTROPLATER. 

shortly be such an improvement in health that the workman 
will hardly be thought the same individual. 

After this experience a dimness remained for months as 
if a mist came between the eyesight and the things looked 
at. Toward evening it became worse, accompanied by a 
very languid feeling and a desire for sleep. The morning 
found one comparatively well, yet with a feeling of restless- 
ness, an acid stomach, a pale visage, sharp features, eyes 
sunken and with dark circles. These effects developed 
slowly. This experience lasted over twelve years. 

The foregoing will serve as a note of warning to all en- 
gaged in the business. There is no doubt, however, that 
these effects will not be experienced if the workroom be 
well ventilated. The author now uses for ventilating pur- 
poses the La Rue electric fan (see illustration on page 117), 
made by the Crocker-Wheeler Electric Company. Platers 
are cautioned to abstain from fluids of an alkaline nature. 
It is far better to drink acidulated water or soda water 
than anything alkaline. Milk with a little seltzer is 
preferable. 




STRIPPING METALS. 




NUMBER of the latest processes and applications 
now in use for stripping metals are reproduced. 
Electro-chemistry is continually making ad- 
vances, and a knowledge of the latest formulas will prove of 
immense advantage to platers. Experience comes as the 
years roll on, and there are few engaged in art or industry 
who have not felt that the more they knew the better for 
them. Those who have not experienced this feeling have, it 
is safe to say, fallen out of the race. To the victor belong 
the spoils ; to the educated workman belong the gains. 
This is as true now as ever it was at any period in the world's 
history. The formulas here given will be found of great 
service to those making use of them. The first is 

Stripping Tin from Tinned Iron. 

According to the Naef process scraps of tinned iron 
are suspended in a leaden vessel containing a solution of 
tin. The tinned iron scraper forms the anode and the ves- 
sel the cathode. The tin is deposited on the vessel as a 
metallic slime. 

In the new process of Rayund the solution used is 
protochloride of tin, acidulated with hydrochloric acid and 



120 THE PRACTICAL ELECTROPLATER. 

possessing a density of from 5 to 6° Baume. The voltage 
necessary for a bath is from three-quarters to 1%. 

Stripping Gold and Silver. 

When it is desired to strip gold from any metal it will 
be found more difficult to strip fine gold than lower grades. 
A good formula for this purpose is as follows : 

Cyanide of potassium. 
Soft water. 

A strength of from 15 to 20 Baume hydrometer 
should be obtained. The articles must be well shaken in 
the bath. Cast brass articles must also be well shaken in 
the solution, otherwise the high intensity of the current 
will widen the pores of the brass. For every square foot 
from 25 to 50 amperes are needed. 

In stripping silver the solution need not be so strong 
by from 5 to io° Baume hydrometer. Consequently the 
current need not be so strong. It is of course understood 
that the anode should have double the surface of the 
cathode. For example, if the object to be stripped be one 
square foot in area, the cathode or sheet of copper should 
be double that size. In carrying out this process the con- 
nections are the reverse of an ordinary plating or deposit- 
ing bath. The copper sheet should be connected with the 
positive pole, and the article with the negative pole. The 
dynamo used for this purpose should not be less than 100 
amperes and 10 volts. 



WATCH CASE PLATING. 



,0R plating watch cases many experiments have 

been made by the author, with the result that 

Lk? a satisfactory method was eventually arrived at. 

Every plater should know that if any silver be contained in 

the alloy for plating it will prove an annoyance and tend 

to tarnish the color while the articles plated are in use. 

The formula for the alloy used in this plating is as here 

given : 

One ounce of fine gold. 

Three pennyweights of oreide. 

Half a pennyweight of nickel. 

Put the above in a crucible and smelt, cast it into an in- 
got, and roll in a large sheet. This sheet is called the anode. 

The nickel is used instead of silver, as it has the same 
color, will not tarnish as easily, and will give a bright 
plating. 

The following formula should be used for dissolving 

the anode : 

One gallon of water. 

Three ounces of cyanide of potassium. 

Put this solution in a jar or other vessel. Take a 
porous cup, fill it with the solution and place it in the jar. 
In the cup place a sheet of platinum, which must be con- 



122 



THE PRACTICAL ELECTROPLATER. 



nected with the positive pole ; the anode of gold should be 
placed outside the porous cup in the jar containing the 
cyanide of potassium solution. The anode is connected 
with the negative pole. The current must then be let run 
through the solution until enough gold is dissolved. This 
can be ascertained by weighing the gold from time to time. 
When enough gold has been dissolved the solution in the 




Hot Bath for Watch Case Gilding. 



jar, together with that of the porous cup, should be poured 
into an evaporating dish (see illustration) and heated. It 
is then ready for working. The watch case should be 
thoroughly polished and well cleaned before it is placed in 
the bath. Otherwise the gilding on the case will not be 
bright. 

The proportion of gold is three pennyweights for 
every gallon of the solution in order to obtain a bright 



FOOT LATHE FOR WATCH CASES. 123 

finish. If the shade obtained is too white, a little chloride 
of gold should be added. It must be well understood 
that water must be added in proportion, together with 
cyanide, when the solution requires a little chloride of 
gold. 

This solution is one of the most important in tne 
market. The success of the operation depends largely on the 
ability of the workman. He should not be discouraged if 




Evaporating Dish. 

he fails, but should endeavor to ascertain the cause of his 
failure. If the bath becomes weaker a little more chloride 
of gold should be added, and the workman find for himself 
the required shade. 

Foot Lathe for Polishing Watch Cases, Etc. 

On page 124 an illustration is given of a foot lathe for 
polishing and scratch brushing watch cases or any other 
description of work. For polishing watch cases with this 
foot lathe crocus must not be used, but fine powder mixed 
with oil. To wash the goods benzine or any other alkaline 
liquid may be used. 



124 THE PRACTICAL ELECTROPLATER. 

In finishing up with rouge do not make use of hot 
rouge, because the latter sticks in the chucks, and a nice 
bright color cannot be obtained. Use fine powdered rouge 



Foot Lathe for Watch Cases, Etc. 

mixed with water or alcohol. By following these instruc- 
tions the workman will produce satisfactory work. 

On the face of every chuck a piece of walrus leather 
must be cemented with shellac or glue. 



GENERAL RULES FOR ELECTRO 
PLATING. 



„ ONSIDERABLE cost would have been incurred 
tffy 




if illustrations had been made for every subject 
treated of in this work. It is therefore hoped 
that the reader will understand thoroughly the various 
processes laid before him. Under the head treated of in 
this chapter a few rules as to the conduct of work are 
given. In the first case a workshop should be thoroughly 
ventilated. Each hot bath should be placed under a chim- 
ney ; but if that is an impossibility a good sized ventilator 
will suit. The reason for this is that the fumes arising 
from the cyanogen are very unhealthful, as spoken of in 
another chapter. Second, there must be two kettles 
filled with potash for cleansing purposes ; one of a low 
degree of strength, from 2 to 4 Baume hydrometer, for 
removing the grease from the soft metals, as tin, lead, 
zinc, britannia metal or similar alloys. The second kettle 
should have a strength of from 5 to io° Baume for 
iron, steel, brass and like alloys. Both kettles should be 
kept at the boiling point. Third, there should be a jar 
containing hydrochloric acid in which to dip cast and 



GENERAL RULES FOR ELECTROPLATING. 127 

wrought iron goods for a few seconds to make the articles 
clean and bright. Fourth, there should be two earthenware 
crocks for brass dipping. 

One jar is for vitriol and water of a strength of io° 
Baume, usually known as pickle. The brass goods must be 
put in the pickle for a few minutes before they are placed in 
the aquafortis. Then pass them through the aquafortis for a 
few seconds and afterward place them in the bright dipping. 
Bright brass dipping is composed of two parts of sulphuric 
acid, one part of nitric acid, a handful of salt and a handful 
of soot. There must also be two gold solutions, one for ob- 
taining a heavy coat and the other for securing a nice 
bright color. If the latter becomes so that it does not give 
a satisfactory rich color the solution must be thrown in the 
first one and a new one made. A copper solution is in- 
dispensable in the plating room, because cast and wrought 
iron, steel, tin, lead and the different alloys of german 
silver must be plated before being dipped in the gold 
solution. In Great Britain and France the majority of 
platers copper every piece of bronze before gilding, after 
which a rich color is obtained. Scratch brushes and soap- 
roots are used for cleaning the articles. A large tank of 
cold water must also be in the room for rinsing goods. A 
kettle of hot water must also be on hand, through which to 
pass the goods, after which they are put in sawdust to dry. 
Burnishing then follows. The best burnisher is bloodstone 
or agate. To make the burnisher work smoothly use 
lukewarm soap water. To this there may be added a small 
quantity of potash. From time to time the burnisher 
should be rubbed against a piece of emery paper, the finest 



128 THE PRACTICAL ELECTROPLATER. 

that can be obtained. The baths numbered i in the 
illustration of an electroplating plant herewith given con- 
tain gold, silver, striking silver, copper, brass and nickel 
solutions respectively. Each bath is connected with a 
rheostat. No. 2 is a rinsing bath ; No. 3 is a sulphate of 
copper solution ; No. 4 is a pot containing cyanide of 
potassium with which to remove tarnish ; No. 5 is a trough 
with a faucet above, and Nos. 6 and 7 are potash kettles, 
containing potash of different degrees of strength, for tin, 
zinc, and britannia metal, and all alloys attacked by 
alkalies. 




NICKEL PLATING. 




§K 



HEN nickel plating was first discovered much 
secrecy was, unnecessarily be it remarked, 

kp JW observed about the process. Now that this 

plating process has been so simplified it is to be found in every 
metal working shop. On December 8, 1869, Mr. Isaac 
Adams, of Boston, Mass., took out a patent for fifteen years 
for a new formula for a nickel bath, by means of which 
he claimed to deposit galvanoplastically plates of pure 
nickel, and to recoat with this metal the other metals or 
alloys used in jewelry and watchmaking. At the same 
time he patented a process for purifying nickel, which the 
trade prior to that had always turned out mixed more or 
less with other metals or metalloids. He gave the prefer- 
ence to bichloride of nickel and ammonia, or, better still, to 
bisulphate of nickel and ammoniac. 

A solution of practical value consists of three-quarters 
of a pound of double sulphate of nickel and ammonia to 
each gallon of water used. Inclose the sulphate in cheese- 
cloth bags and suspend the latter in the top part of a vat 
about three parts full of water until the sulphate is com- 
pletely dissolved. It will be ready for using after it has 
been stirred well for the purpose of thoroughly mixing It 



130 THE PRACTICAL ELECTROPLATER. 

will be found that the resistance of such a solution is 
reduced 25 per cent, if 10 per cent, of common salt is 
added, and a whiter and more flexible deposit is obtained. 

Generally only a small amount of nickel can be deposited; 
if this quantity is exceeded, the deposit will come away 
from the metal or copper beneath. All that is requisite is 
a thin coating, for nickel is very hard indeed and will stand 
a great deal of friction. It will not corrode or become 
tarnished, as steel will, and consequently it has taken the 
place of the latter metal in plating iron or brass. It wears 
exceedingly well, presenting a comparatively good appear- 
ance after considerable use, a quality which is sufficient 
recommendation for using it The solution should never 
be stronger than 6° Baume. 




PROCESS FOR 
PLATING DIRECTLY ON IRON 



^|g) N this process the anode is attached to the articles to 
Jt be gilded in a distilled or rain water bath of a warmth 
^1 of from 70 to 8o° centigrade, a strip of copper, iron 
or carbon serving as a cathode. The magnetite is formed 
directly by the action of the current. After an hour or 




Evaporating Dish. 

two the operation is finished. If the current is too strong 
the oxide deposited is pulverulent and does not adhere, and 
will roughen the goods and make them porous. The first 
coat is non-adhering, the second will adhere better, and the 
last coats are as hard as the metal itself. The hardest 
steel is the easiest to coat. For soft iron it will be neces- 
sary after the first operation to attach it to the cathode, in 



i 3 2 THE PRACTICAL ELECTROPLATER. 

order to reduce the oxide, and then to reverse the position ; 
that is, to the anode. By this means a strongly adhering 
deposit will be obtained. A piece of iron oxidized by this 
process and immediately placed in a bath composed of cop- 
per, silver or gold will be covered by a coat of the metal 
used that will adhere perfectly. 

In Solingen, in Germany, the cutlery works of which 
place closely rival their English competitors, who are ad- 
mittedly the first in the world, cutlery the steel of which 
has been highly polished a deep black color has the grease 
removed before gilding. The gilding is prepared in the 
same way as we prepare it for brass, only it is very weak 
and poor in gold. Not half the usual quantity of gold is 
used. Before the steel is placed in the gilding it must be 
dipped into a weak alkaline copper solution prepared with 
caustic soda. 




DEPOSITING GOLD ON OTHER 

METALS. 




^HERE are many varieties of solutions for de- 
positing gold on other metals. It is deemed 
advisable here to give the most direct method. 
Finely laminated gold is dissolved in aqua regia in the 
manner that silver is dissolved in nitric acid. Aqua regia 
consists of two parts of hydrochloric acid and one part of 
nitric acid. The gold must be evaporated in an evaporat- 
ing dish nearly to dryness, for the purpose of expelling any 
excess of acid. The residue is then dissolved in a small 
quantity of water. The residue is called chloride of gold, 
and can be used in different varieties of solutions. The 
method of preparing a gilding solution of gold fulminate is 
given below. It should be remembered that fulminate of 
gold is very explosive when it is in a dry condition. Ful- 
minate of mercury and fulminate of silver can be prepared 
in the same way. Fulminate of mercury is largely used by 
pyrotechnists in their work for the purpose of producing 
explosions. 

Preparing a Gilding Solution by Fulminate 
of Gold. 

Precipitate the gold as fulminate by adding ammo- 
nium hydrate to a dilute solution of chloride of gold until 



134 THE PRACTICAL ELECTROPLATER. 

the precipitate ceases to form. Then thoroughly wash the 
precipitate, and while it is yet in a wet state add a solution 
of cyanide of potassium until it is exactly dissolved. The 
precipitate must be dissolved in cyanide immediately after 
washing, because it is very dangerous when dry, as men- 
tioned above. 

The formula is as follows : 

Ten pennyweights of gold. 

One hundred pennyweights of cyanide. 

One gallon of water. 

Gilding by Immersion. 

As will be noted throughout this work, no trouble or 
expense has been spared by the author in his endeavor to 
give the reader the best of the various methods in use in 
the electroplating world, both in the United States and in 
Europe, Processes to which no value attaches have been 
ruthlessly cast aside, whether advocated by well-known 
men in the business or not. Rotten branches are of no use 
to a tree, and the same may be said of formulas for plating 
which have no value, in fact have really no raison d"eti'e. 
With this idea uppermost, and because the process is in- 
noxious to health (a very important point to electroplaters), 
the process of the famous George R. Elkington, of Birming^ 
ham, England, for gilding by immersion is here introduced 

It is as follows : 

One and one-half parts chloride of gold. 
Sixty parts hydrogen potassium carbonate. 
Two hundred parts of water. 

This solution should be boiled for two hours, during 
which time the mixture, which is yellow at first, becomes a 



GILDING BY IMMERSION. 135 

green color, when it is ready for use. Copper and brass 
goods are gilded by dipping them in this hot solution for 
about thirty seconds. Any other metal, tin, nickel or ger- 
man silver for instance, must be copper or brass plated 
prior to immersion. 

While on this subject it may be noted that Langbein's 
process is one of the best for this purpose. It is as fol- 
lows : 

One-half drachm chloride of gold. 
Nine drachms potassium cyanide. 
Two and three-quarters drachms crystallized 

sodium phosphate. 
One and one-half drachms pure caustic potash. 
One quart of water. 

Dissolve the chloride of gold and the potassium cyanide 
in part of the water and the sodium phosphate and caustic 
potash in the other part. Then mix the two solutions and 
heat the mixture to the boiling point. It is better to dip 
the subjects to be gilded in the partly used solution, and to 
finish in a newly prepared one. 

The author made many experiments with this process 
and found it to be very advantageous to double or triple 
the quantity of caustic potash recommended by Langbein. 
The solution can be used in an iron kettle, as spoken of 
under " Dip Gilding." This gilding will be found of much 
service to makers of brass imitation jewelry who work by 
the basket and whose aim is to produce goods as cheaply 
as possible. 

Before finishing this subject it is well to remark that 
gilding by immersion is very important when dealing with 



136 THE PRACTICAL ELECTROPLATER. 

watch movements. To obtain a good result in that kind 
of work the workman must carefully follow the directions 
here given. After removing the grease from the move- 
ments in a potash solution, pass the goods in nitric acid 
and then in a well prepared bright dipping. The success 
of this dip gilding depends on good bright dipping. One 
good operator is able to turn out daily from ioo to 200 
pounds of movements. 




RECOVERING FROM OLD 
SOLUTIONS. 



Recovering Gold. 



y£^r^ VERY little makes a mickle, runs the old Scotch 
1, ^ proverb. The plater perhaps does not put it 
^^z2/ that way when he is recovering gold and silver 
from old solutions or is keeping a strict eye on the sweep- 
ings ; but the intention is there all the same. One of his 
duties is to recover gold from old solutions ; consequently it 
is appropriate to give space to a method for so doing. Add 
hydrochloric acid in excess to the solution, in the open air 
or in a room where the fumes will quickly disappear, for 
the purpose of avoiding inhaling the noxious fumes of 
hydrocyanic acid ; siphon off the clear liquid, and then col- 
lect the cyanide of gold. Add water and precipitate the 
gold with ferrous sulphate Then filter the solution and 
resort to smelting. 

A simpler way to perform this operation is by electric- 
ity. Hang a sheet of copper in the old solution, and con- 
nect it with the positive pole. Also hang a sheet of plat- 
inum in the solution and connect it with the negative pole. 



138 THE PRACTICAL ELECTROPLATER. 

Let the current run for a few days, when all the metal in 
the bath will be found deposited on the sheet of copper. 
It is of course understood that a quantity of cyanide is 
added for the purpose of aiding the deposition process. 

Recovering Silver. 

In this process hydrochloric acid must be added in ex- 
cess and the clear liquid siphoned off. Then collect the 
precipitated silver chloride, dry and fuse in a clay crucible 
with twice its amount of pearl ash and borax ; make it into 
an ingot, allow it to cool, and then detach the slag by strik- 
ing it with a hammer. 




BLACK PLATINUM OXIDIZING. 



SECOND FORMULA. 




^^AKE a strip of platinum, finely rolled, and dis- 
solve it in an evaporating dish in aqua regia. 
After the aqua regia has evaporated entirely 
there will remain a brown mass of liquid, something like the 
consistency of molasses. This is chloride of platinum. Add 
about a gill of sulphuric ether or alcohol, and then dissolve 
the chloride in a quart of cold water. Ten pennyweights 
of platinum will be sufficient for a pint of water. To se- 
cure a nice black tone, say an ebony hue, the goods must be 
cleaned and then scratched with a scratch brush. The so- 
lution must by all means be kept at the boiling point. If 
partly white and partly black be desired, take a camel's hair 
pencil and paint the part to be black with the liquid. 
Keep the subject over an alcohol lamp, so that it be kept 
hot until the required effect presents itself. The same 
black tone can be produced by adding tincture of ferro- 
chlorhydric to the chloride of platinum. Another method, 
which will prove equally successful, is to take 10 penny- 
weights of platinum, half a glass of hydrochloric acid, and 
a pint of water. This mixture should be boiled in an 



HO THE PRACTICAL ELECTROPLATER. 

evaporating dish and the article to be oxidized should be 
dipped into it. 

Black oxidizing can be obtained in a different manner, 
but the operator must look to the economical side of 
the work in hand. To make a cheap black oxidation, satis- 
factory results can only be obtained by means of electricity. 
To an old exhausted brass solution add a quantity of 
arsenic acid and work with a brass anode. In case there is 
no old solution, dissolve cyanide of io° Baume in water 
with a strong current. By this means a nice black color 
will be obtained cheaply. 




WEIGHTS AND MEASURES. 






^HE gram is the unit of weight in the metric 
QJ or French system of weights and measures. 
Theoretically it is the weight in vacuo of a 
cubic centimeter of distilled water at the temperature 
of maximum density, assumed to be 4 C. or 39*1° 
Fahr. Practically it is the thousandth part of the weight 
of the kilogram in platinum deposited on June 22, 1799, 
in the Palace of the Archives in Paris, by the inter- 
national commission appointed to fix the standards, who 
that day completed their work. The original determina- 
tion of this standard was made in 1795. I* was adopted 
as representing exactly the weight in vacuo of a cubic deci- 
meter or water under the conditions above named. Its 
weight in British grains has since been carefully ascertained 
on three occasions, viz. : by Hassler, chief of the United 
States Coast Survey, in 1832 ; by Kupffer, of St. Peters- 
burg, in 1 841 ; and by Miller, of London, in 1844. These 
determinations are severally as follows : Hassler, 15,433*- 
1669 ; Kupffer, 15,43236186 ; Miller, 15,432-34847. Miller's 



142 THE PRACTICAL ELECTROPLATER. 

determination was adopted by the British Standards Bureau, 
and is generally accepted. But as the officially adopted 
length of the meter in England is 39.37079 inches, and 
the adopted weight of the cubic inch of distilled water in 
vacuo, at 62 Fahr. (252724 grains) reduced by Miller's co- 
efficient to 39'i° Fahr. is 253*00452 grains, it results from 
the combination of these numbers that the standard kilo- 
gram deposited in the Palace of the Archives is 7771 18 
grains too light. Kupffer, on the other hand, found the 
weight of the cubic inch of water in vacuo at 13^6° R. = 
16*67° C.=62° Fahr., to be 252*598 grains ; and taking this 
with his determination of the weight of the standard kilo- 
gram (which exceeds that of Miller only by the minute 
fraction 0*01312 gr.), a cubic centimeter of water at 
maximum density weighs in vacuo 1,000*0115 grams, or only 
about one-sixth part of a grain more than the standard 
kilogram. 

The true weight in British grains of a cubic inch or of 
any other given volume of water is still unsettled ; and it is 
equally uncertain what is the amount of discrepancy between 
the actual or legal and the theoretic weight of the standard 
kilogram. 

The gram, equal to 15.43 grains, though the unit base 
of the system of metric weights, is the practical unit only 
where small quantities are concerned, as in chemistry, 
&c. The usual commercial unit is the kilogram, equal 
to 2*20462 pounds avoirdupois. It should be observed that 
this equivalent of the kilogram, which is commonly re- 
ceived, is a weight in vacuo, and involves consequently for 



WEIGHTS AND MEASURES. 143 

ordinary uses a trivial error, which is of no practical im- 
portance. 

AVOIRDUPOIS WEIGHT. 

Dram, equals 1.17718 grams 

Ounce, 28.3495 

Pound, 0.4535926 kilograms 

Quarter, 12.6956 

Hundredweight, 50.802 

Ton, 1016.048 

TROY WEIGHT. 

Grain, equals 0.064798 grams 

Pennyweight, i.555 T 7 

Ounce, 31.1035 

Pound, 0.373242 kilograms 

MEASURE OF CAPACITY. 

Pint (liquid), equals 0.4731 litre 

Quart (liquid), 0.9463 " 

Gallon (liquid), 3.7852 " 

FRENCH MEASURE OF CAPACITY. 

Centilitre (100th of a litre), equals 0.021 1 pints 

Decilitre (10th of a litre) 0.2113 

Litre (1 cubic decimetre), .... .... 1.0567 

Decalitre (10 litres), 2.6417 gallons 

Hectolitre (100 litres), 26.4177 " 

Kilolitre (1 cubic metre), 264.177 bushels 



144 THE PRACTICAL ELECTROPLATER. 

MEASURES OF WEIGHT. 

One milligram, equals .0154 grains 

One centigram, 1543 " 

One decigram, 1-5434 

One gram, 154340 

One litre equals about 34 fluid ounces. 




LIST OF MATERIALS NECESSARY 
FOR A PLATING SHOP 



Dynamo or Bunsen battery. 

Nitric acid. 

Hydrochloric acid. 

Sulphuric acid. 

Sulphate of copper. 

Sal ammoniac. 

Scales and weights. 

Silver and gold anodes rolled out to a moderate thick- 
ness. 

Burnisher. 

Borax. 

Bisulphide of carbon. 

Brass rod to suspend articles to be plated. 

Common salt. 

Caustic potash. 

Carbonate of potash. 

White sand for blower. 

Jar for stripping solution. 

Plumbago. 

Fine gold and fine silver for solution. 

Nitrate of potash. 

Nitrate of mercury prepared by dissolving mercury in 
nitric acid. 



146 THE PRACTICAL ELECTROPLATER. 

Acetic acid. 

Circular scratch brushes. 

Soaproots for scratch brushes. 

Scratch brush lathe. 

Buffs (felt, cotton and leather) for polishing. 

Gilding bath of glass or stoneware. 

Plating bath of wood or stoneware. 

Several brushes, different sizes, of one, two, three and 

four rows each. 
Chamois leather. 
Rouge. 
Mercury. 
Evaporating dish. 
Rosin. 

Cyanide of potassium for gold and silver bath. 
Vessel for cleaning work. 
Rinsing vessels. 
Glass measures. 
Porous cell. 
Binding screws. 
Filtering paper. 
Boxwood sawdust. 
Potassium for gold and silver baths. 
Emery cloth, different grades. 
Copper wire. 

Thin copper wire for slinging. 
Powdered pumice stone. 
Flat and round pliers. 



BATH FOR AGITATING. 






^HE illustration herewith given depicts a bath used 
for electrotyping silver and copper plating and 
for etching. It is a very valuable adjunct to 
an electroplating establishment ; indispensable, in fact, 




Bath for Agitating. 



for the purpose of producing good work. The high in- 
tensity of the current forms the minute globules of gas 
which may be seen now and then on goods. The agita- 
tor prevents this undesirable state of things and expels 



148 THE PRACTICAL ELECTROPLATER. 

the gas. The agitating bars, cathodes (or articles to be 
plated), anodes and electro-magnets attached to the bath 
and connected with the dynamos are depicted in the 
illustration. 

This electric agitator is a very ingenious contrivance 
for keeping the electrolyte in motion when plating with 
dense or cold solutions. This effect is ordinarily produced 
by mechanical means, necessitating the employment of 
shafting and belting, which in the event of the vats not 
being in line become very expensive. Blowing air through 
the solutions and using circulating pumps involve consid- 
erable expense, and objection must therefore be taken to 
their use. Electricity will be found to be the best power. 
An arm is drawn up quickly by means of magnets and 
allowed to fall gradually by its own weight. This motion 
entirely overcomes any tendency in the electrolyte to form 
layers of varying density, and a consequently uneven 
plating, and at the same time the action is not so violent as 
to stir up the sediment at the bottom of the vat. Another 
advantage of this agitator is that it can be left working 
during the night by a battery or an accumulator. 



ETCHING COPPER BY ELECTRICITY. 151 

brush. The plate is now ready for mounting, routing or 
sawing away the edge, and nailing to a block of mahogany 
of a thickness to make the whole just type high. 

Copper is extensively used now, and half tones on this 
metal command a higher price in the market than zinc 
work. This process is very simple and gives excellent 
results. 



ETCHING COPPER BY ELECTRICITY. 

There are very many processes for etching. It is 
hardly necessary to repeat that electricity is playing a very 
important role in the electroplating trade. 

In the baths worked by electric current there is gen- 
erally attached to the positive pole a soluble anode or plate 
of the same metal of which the bath is composed. This 
plate or sheet is dissolved as the object fixed to the other 
(or negative) pole receives the deposit, keeping the liquors 
well saturated. 

Simple observation of this process led to the idea of 
engraving by electricity. It was evident, in fact, that in 
recovering certain parts of the anode with an isolating sub- 
stance the others that were not covered would be dissolved 
slowly and would engrave themselves in more or less uni- 
form manner, while the preserved parts, conserving the 
original thickness of the anode sheet, would form reliefs. 
Electric etching is carried out in various ways, which, how- 
ever, differ very slightly. Most of these methods are more 



152 THE PRACTICAL ELECTROPLATER. 

or less familiar to the reader. Ordinarily a bath analogous 
to the metal to be engraved is employed. Thus baths of 
sulphate of copper are employed in etching sheets of that 
metal, baths of sulphate of zinc for graving on zinc, and 
baths of gold and baths of silver for corresponding metals. 
Nevertheless, engraving may be done on copper and zinc 
by working the battery on baths composed solely of water, 
slightly acidulated by azotic, chlorhydric, sulphuric or 
acetic acid. This latter method is not now generally used. 




ELECTRICAL SMELTING 

AND 

PRODUCTION OF ALUMINUM. 






^HE Cowles process of electrical smelting and pro- 
ducing aluminum alloys is playing an important 
part in metallurgy. By it materials are ob- 
tained which are curiosities found only in chemists' labora- 
tories. Silicon and chromium have already been obtained 
in the form of alloys with other metals in practical quanti- 
ties and at small cost. Other rare metals have also been 
obtained experimentally ; but attention, so far, has been 
turned to the production of aluminum, as offering the widest 
field for the products of the furnace. An account of the 
machinery for producing the current and of the products 
obtained by the use of the process will prove of much value 
to the reader. The illustration shows a section through the 
longitudinal centre of a furnace built in the beginning of 
1888 at the works of the Cowles Syndicate Company, Lim- 
ited, at Milton, Stoke-on-Trent, England. The inventors, 
Eugene and Alfred Cowles, being engaged at their Ameri- 
can works, the task of selecting and arranging the plant, 



ELECTRICAL SMELTING, ETC. 155 

buildings, furnaces, &c, was placed in the hands of Mr. 
William Boby, of London, to whom the author is indebted 
for this description, and his partner, S. G. Browne, and car- 
ried out between October, 1887, and April, 1888. 

The furnace is an oblong receptacle, the internal dimen- 
sions being 5 feet long, 3 feet 3 inches deep and 20 
inches wide It is built below the floor line and lined with 
fire bricks Into the ends are built cast iron tubes, in- 
clined, as shown for convenience in working the electrodes. 
On the ends of the tubes are covers with bosses upon them, 
through which the electrodes pass. On to the covers are 
screwed blocks of wood surrounding the bosses. Near the 
outer ends of the electrode rods are easily removable 
clamps, each of which holds a nut, through which a screw 
having a T handle at its outer end passes, while its inner 
end rests against the wooden block. The rotation of this 
screw moves the electrode inward or outward. The top of 
the brickwork is covered by iron plates, and an iron cover, 
as shown, is placed over the mouth of the furnace. In the 
cover is a hole through which the gases issue as they are 
driven off by the heat in the furnace. The electrodes con- 
sist of carbon rods 2^ inches in diameter, and nine of 
them are attached to each electrode rod. The attach- 
ment, as shown in the illustration, consists of metal cast 
around the ends of the carbons and of the electrode 
rod, so as to form a conductor in perfect contact with the 
whole of the parts connected. The metal from which this 
attachment is cast is selected to be suitable for the alloy to 
be dealt with in the furnace, as, although in comparison 
with the actual charge it is not subjected to a very intense 



156 THE PRACTICAL ELECTROPLATER. 

heat, yet the metal of which it is composed is found to 
exercise a slight influence upon the furnace product. 

Here, then, we have a covered furnace, provided at the 
ends with two electrodes, capable of being easily moved 
apart. It is extremely simple, without complication of 
parts, and built entirely of cheap materials, excepting the 
electrode rods and carbons, the former being of copper and 
permanent, while the cost of the renewal of the latter is a 
small item in comparison with the amount of work done. 
The application of the furnace is as follows : The two 
electrode rods are connected to the two dynamo leads, the 
cable connected to the positive pole sending the current 
into the left hand electrode, whence it travels through the 
charge, where it meets with the resistance which causes the 
heat, and passes by way of the right hand electrode into the 
cable connected to the negative pole of the dynamo. The 
resistance is caused by the particles of carbon mixed in the 
charge. The current acts independently of the structure 
of the furnace, acting simply on the charge in immediate 
contact with the carbon by means of which the heat is pro- 
duced. An enormous heat is developed, and fire bricks < 
not capable of withstanding it. Charcoal is the most c<_ 
venient form of non-conductor of which to form a protective 
lining, but in a short time the intensity of the heat converts 
it into graphite, so that it loses its non-conductive proper- 
ties. To renew the charcoal lining frequently entailed 
considerable expense, and formed a difficulty which was 
overcome by dipping the partially graphitized charcoal into 
limed water, the lime being found to render the charcoal 
again sufficiently refractory. The liming process is as sim- 



ELECTRICAL SMELTING, ETC. 157 

pie and cheap to carry out as it is satisfactory. The char- 
coal is put into a cistern of limed water, and afterward dried 
in a revolving steam jacketed cylinder. When charging a 
cold furnace charcoal is put into the bottom and lightly 
beaten down until it forms a fairly firm bottom of sufficient 
thickness. The electrodes are run inward till their ends 
nearly meet in the furnace, and the charge is then put into 
the centre of the furnace and surrounding the electrode 
ends. The charge for copper alloy consists of nearly 300 
pounds of materials, about a fourth being ore broken up 
small, about 4 per cent, of carbon, a good deal of which is 
supplied by means of broken up slag taken from a former 
heat, slag to the amount of about 10 per cent, being intro- 
duced, and the balance copper. If iron alloy is required 
the charge consists of a larger proportion of slag, the iron 
being broken into small pieces. The copper is granulated 
by being poured into water when in its molten state. 

The ore used is sometimes corundum, which for some 
time was the only ore employed by the Messrs. Cowles in 
their process ; but the ore made use of at the Milton works 
bauxite, which after repeated experiments was found to 
swer equally well and at a fraction of the cost. The 
charge is prevented from spreading out laterally while 
being inserted, in which case some portions of it might be 
too distant from the electrodes, by two pieces of sheet iron, 
connected by a distance piece, placed one on each side of 
the electrodes ; the charge is put in between them, and 
charcoal then filled in between the sheet iron and the sides 
of the furnace, after which the sheet iron is withdrawn, the 
top of the charge covered, and the ends of the furnace 



158 THE PRACTICAL ELECTROPLATER. 

filled up with charcoal to the depth of a few inches above 
charge and electrodes. The iron cover is then adjusted 
over the furnace and luted round its edges with fire clay, to 
render it as gas tight as possible ; the furnace is then ready 
to receive the electric current. At first the full amount of 
current is not applied ; the engine is started at a moderate 
speed, so as to provide from about 2,000 to 3,000 amperes. 
This finds its way through the charge and gradually heats 
it and the lining immediately surrounding the ends of the 
electrodes. As the ore and metal of the charge become 
fused the resistance decreases, when the speed of the en- 
gine is gradually increased, and the electrodes drawn apart 
until the whole of the ore and metal in the charge is fused, 
before which time, having a larger body of materials to act 
upon, the full 5,000 amperes of current is flowing through 
the charge. Immediately afterward the electrodes are with- 
drawn the necessary distance and the entire charge fused 
(which takes an average of one hour and thirty minutes to 
one hour and forty minutes), the engine is slowed to a few 
revolutions per minute, the shunt exciting current is switched 
off the magnets so as to break the field, and the brushes 
are raised ; the electrode rods are then disconnected from 
the leads and another furnace is connected to the current. 
The slowing down of the engine, disconnection and recon- 
nection of leads, and starting again occupies a few minutes 
only. 

When the current flowing through the furnace begins 
to produce considerable heat a light smoke commences to 
rise from the hole in the top cover. When it has reached a 
fair volume a light is applied and it burns brightly, the gas 



ELECTRICAL SMELTING, ETC. 159 

given off being carbonic oxide, which, although of an ex- 
plosive character, simply burns quietly, though vigorously, 
as it comes off. If after the engine is stopped the lid be 
raised immediately the heat is seen to be of a very intense 
nature. On the first occasion of this kind at Milton, Mr. 
Eugene Cowles, who was present, remarked to Mr. Boby 
that they probably had before them the highest tempera- 
ture ever produced in England. No method has been de- 
vised for obtaining any idea of the temperature ; it seems 
probable, however, and indeed there can, Mr. Boby thinks, 
be little doubt, that the metals in the charge are volatilized, 
after the more volatile oxygen has been driven off, and 
rising in that condition from the neighborhood of the 
electrodes meet the cooler portions of the lining and be- 
come precipitated, the metallic alloy being found in the 
form of a slab on the charcoal lining below the electrodes. 
It is assumed that the aluminum combines with the metallic 
base of its alloy while both are in the gaseous condition ; 
it is certain that the alloys formed by this process possess 
a completeness of union between their component parts, a 
homogeneity and strength, which, as far as has been ascer- 
tained, is superior to those qualities as found in aluminum 
alloys otherwise compounded. The furnace had to be al- 
lowed to cool before the contents could be removed and the 
charge renewed. This proved a source of loss and delay, 
and an improved set of furnaces is now in use, of similar 
form to that in the illustration, but raised above the ground, 
and having a tap hole from the side into the interior, by 
means of which the metal is run out in a molten condition. 
The furnace also is recharged without being allowed to 



160 THE PRACTICAL ELECTROPLATER. 

cool, an important economy being thus effected over the 
original method. 

The production of aluminum at the Milton works has 
reached about 200 pounds of actual aluminum per twenty- 
four hours, when the aluminum was produced as an alloy 
with copper ; or, if the alloy had iron for its base, a less 
amount was obtained, about 150 pounds. The average 
number of runs per twenty-four hours is about twelve to 
fourteen, so that about 15 to 18 pounds of pure aluminum 
(embodied in the alloy) per run, when producing bronze, 
is obtained. The attendance required upon the furnace is 
small ; two youths attend to the adjusting of the electrodes 
for the regulation of the current, and to the connecting to 
and disconnecting from the dynamo leads ; while two men 
weigh out the ore, &c, charge the furnaces, and run the 
molten metal off. The ferro-alloy frequently comes from 
the furnace complete and ready for the market, but in some 
cases it contains a proportion of the charcoal lining me- 
chanically mixed with it. When this occurs it is remelted 
in an ordinary furnace, the charcoal floats on the surface, 
and is easily removed. The cupro-alloy comes from the 
furnace in the form of a nearly pure white metal, highly 
charged with aluminum, but by a very simple process it is 
fused and mixed with the necessary amount of copper to 
form a bronze of the required grade. 

Before going into the subject of the finished products, 
a description of the machinery employed for generating the 
current will prove interesting. The boilers, two in number, 
are of the well-known Babcock & Wilcox type. These 
boilers answer well, working day and night, there being no 



ELECTRICAL SMELTING, ETC. 161 

spare boiler, and are fired by means of mechanical stokers. 
They burn rough slack coal, which is quite unscreened and 
contains a large quantity of dust. Their performance is 
very creditable. They are each of 145 horse power nomi- 
nal, and as the engine often indicates from 500 to 540 horse 
power for a considerable time, it speaks well for their quali- 
ties that they supply it with enough steam. They also 
supply steam to three small engines on the works, and a 
small quantity for other purposes. The engine is com- 
pound and condensing, of the tandem form, having cylin- 
ders 23 inches and 43 inches in diameter, with a stroke of 
5 feet. It draws its condensing water direct from a neigh- 
boring canal. The engine is finely designed and well 
finished, built with a special view to high speeds, and runs 
ordinarily at from sixty-six revolutions per minute at the 
beginning of the run to eighty revolutions per minute to- 
ward the end of the run. Its valve gear is not of the trip 
kind, but its three slides are moved by eccentrics, the high 
pressure slide being of the piston form, with another piston 
valve inside it for regulating the cut-off. The current is 
subject to considerable irregularities of flow, which are 
sometimes very sudden, and the efficient regulation of the 
engine is of much importance. The governor acts by turn- 
ing the piston expansion valve, and is quite successful in 
controlling the engine within very narrow limits. An ar- 
rangement is fitted to the governor by means of which the 
speed of the engine can be varied as desired. This gear 
was selected as being more suitable for such quick running 
than the trip gears usually found on engines of this size. 
The engine runs with such absence of noise that, standing 



162 THE PRACTICAL ELECTROPLATER. 

with one's back to it, it is hard to believe that it is working. 
The fly-wheel is 20 feet in diameter, its periphery being 
grooved by ropes, by means of which the power is trans- 
mitted to the dynamo. The engine works under conditions 
unfavorable to economy, owing to the variations in the 
amount of current required by the furnace ; but it was 
found after a careful test, extending over a number of runs, 
that the consumption of common slack coal, and including 
the intervals between the runs, only amounted to 3.1 pounds 
per indicated horse power per hour. An electrical appara- 
tus worked by a small battery is fitted to the stop valve, so 
that the steam can be turned off the engine instantaneously 
by pressing a push button, several of which are fixed to the 
wall and the columns near the dynamo and the furnaces. 
The apparatus opens a cock in the condenser, and breaks 
the vacuum at the same time that the steam is shut down. 
Thus the dynamo and furnace attendants can at once stop 
the engine, should it be found desirable, without having to 
signal to the engineer. 

The dynamo probably furnishes the largest amount of 
current of any machine in existence, its normal output be- 
ing 5,000 amperes at a tension of 60 volts. It is of the 
constant current type, with drum armature. The shaft is 
of steel, 7 inches in diameter, and carried in three bearings, 
two of the latter being placed on each side of the driving 
pulley and one outside the commutator. The driving pul- 
ley is 4 feet in diameter, grooved to correspond with the fly- 
wheel, and its weight is about 2 tons. The central part of 
the shaft is larger, having been made 14 inches in diameter, 
but it has been planed down to 10 inches, leaving, how- 



ELECTRICAL SMELTING, ETC. 163 

ever, four ribs projecting, which act as keys to carry round 
the core. The core consists of disks of Swedish iron about 
18^ inches in diameter, 900 in number, making a total 
length of core of about 36 inches. The winding upon the 
core consists of 128 radial copper bars seven-eighths of an 
inch deep, and three-eighths of an inch thick at the top. 
They are coupled at the ends of the core by means of 
crescent shaped bars forming thirty-two conductors. The 
whole arrangement was thought by the designers to be one 
which would avoid any considerable amount of heating of 
the armature, but in practice this result was obtained, and a 
fan is employed to send a strong current of air of consider- 
able volume through the armature. Originally the winding 
bars were held by thirty-two projecting steel pins fixed to 
the core, but these gave way and were replaced by double 
the number, of larger size, and made from the Cowles Com- 
pany's 10 per cent, aluminum bronze, with a strength 
greatly exceeding that of steel. Steel wire bands are 
wound over the bars to hold them tightly to the core. The 
commutator has sixty-four parts, and is 20 inches long, 
with a centre tightening ring on account of its length. It is 
fitted with eight brushes mounted on a separate ring, and 
the current is carried off by a large number of strips of 
stencil copper. The field magnets are of soft wrought iron 
of the double type placed horizontally. There are four 
turns of 1% inch by 1 inch copper bars round the magnets. 
The machine is wound in series, with shunt coils, which ex- 
cite the field magnets, and a current is produced with a po- 
tential proportionate to the speed of the engine. A sepa- 
rate dynamo was used at first to excite the field, but it was 



i6 4 THE PRACTICAL ELECTROPLATER. 

found unnecessary. The ordinary full working speed of 
the armature is 380 revolutions per minute, though it is fre- 
quently run up to 400, the normal output of 5,000 amperes 
and 60 volts being then somewhat exceeded. The current 
occasionally jumps for a moment to a very high point, owing 
probably to metal in the charge fusing in such a way as to 
suddenly give the current a considerably freer passage. 
The lubrication of the bearings is effected by castor oil 
and water. A safety cut-out is provided between the dy- 
namo and furnace rooms. It is calculated to fuse at 8,000 
amperes. 

In the furnace room is a current indicator having a 
dial fronting to the furnaces and another one on the other 
side of the partition wall in the engine room. The indi- 
cator consists of a solenoid of nine turns, made by casting 
a cylinder of copper and then cutting it spirally by means 
of a parting tool. All of the current passes through this 
coil, which is interposed in the main positive lead. The 
core of the solenoid is geared to the dial spindle. The 
markings of the dials were made by actual experiment 
after the dials were in place ; they extend to 5,000 am- 
peres, an amount of current which sends the hands about 
two-thirds round the dial. Tapped from the main lead is a 
pilot light suspended over the dial in the furnace room, and 
which gives light for reading the latter. The main leads 
from the dynamo consist of bars of copper 3 inches by 1 
inch. There are three of these leads alongside each other in 
the furnace rooms from each pole of the dynamo, and they 
are slightly over 50 feet long in one piece. From these de- 
pend flexible cables connected atone end with the electrode 



ELECTRICAL SMELTING, ETC. 165 

rods, and at the other to flat bars, which are clamped be- 
tween the bars of the leads, and provided with wheels 
which roll along the top edges of the leads for convenience 
in shifting the connections from one furnace to another. 

Very few hands are required to work the process prop- 
er. Besides the two boys and two men named as attend- 
ing to the furnace, the works employ one man each to en- 
gine, boilers and dynamo ; one man and one boy in 
preparing and moving charcoal ; two men in the foundry, 
who standardize bronze and cast ingots, and an occasional 
electrode holder, who also attends to the remelting when 
required of the ferro-alloy. Other men are also employed, 
as there would be in any other works, such as a carter, a 
fitter, a carpenter, a night watchman and a storekeeper ; 
altogether when working double shift, about twenty-five 
men and boys. The plant is small, but there is ample 
space for extension. Mr. Boby found by tests taken over a 
series of runs that a pound of actual aluminum in the 
bronze alloy was produced by 20 electrical horse power, 
and in the ferro-alloy by about 28 electrical horse power. 
Improvements in the details of the process have gradually 
lowered the amount of horse power since starting up, and 
no doubt more may be done in this direction, more par- 
ticularly by the employment of a still larger volume of 
current. 

In the products of the furnace there are two principal 
alloys. The ferro-alloy is ready for the market as it runs 
from the furnace, or it is rendered so with very little labor. 
The amount of concentration of the alloy is not an impor- 
tant point, so long as it is definitely known, the use of the 



166 THE PRACTICAL ELECTROPLATER. 

ferro-alloy being entirely for mixing with other iron, either 
cast or wrought, or (which appears to be its greatest field 
of usefulness) with cast steel. The selling price of the 
ferro-alloy is regulated by the amount of its concentra- 
tion, which is decided by analysis. It is, however, possible 
that it may be ascertainable by other means ; for instance, 
it is known that when the concentration exceeds a cer- 
tain amount the alloy becomes non-magnetic, not being 
attracted by a loadstone. This is a property which may 
possibly be found to be of practical value. A valuable 
property of aluminum, as produced by this process, here 
comes into play, viz., any desired quantity of the ferro-alloy 
can be melted up and it will be quite certain that an analysis 
of a few grains of it will represent the concentration of the 
entire bulk. This quality of equal diffusion is of high 
value when it is considered that by its means a ladleful of, 
say, molten steel will be impregnated with a minute pro- 
portion of aluminum if a small quantity of the broken up 
alloy has been placed in the bottom of the ladle before the 
steel was poured in. The combination of aluminum w r ith 
iron having taken place in the electric furnace, it has never 
been in contact with oxygen, and the very thin film of 
oxide which forms upon the pure metal when exposed to 
the atmosphere, and which causes considerable trouble in 
dealing with pure aluminum, does not come into existence 
in the alloy. 

The use of ferro-aluminum has not hitherto obtained any 
large dimensions in Great Britain ; in the United States it 
is already largely in use. The effect of the alloy upon steel 
is to raise its elastic limit and ultimate strength, while it 



SOLDERS FOR ALUMINUM. 167 

lowers its melting point and facilitates the making of sound 
castings. This latter point will be recognized as of great 
importance. The sale of this alloy in America has reached 
considerable dimensions. 

The effect of ferro-aluminum upon puddled bar iron 
has been investigated with most satisfactory results. The 
tensile strength being raised to 31 tons with 22 per 
cent, elongation, it is stated that the quality is equal to that 
of the finest mild steel. Testimony has been borne to the 
remarkably beneficial effect of this ferro-aluminum as 
applied to cast iron tests, showing that after the iron had 
been cast the aluminum remained in it and continued to 
influence it beneficially even after several remelts. It has 
been held by previous investigators that under such circum- 
stances the aluminum passed off ; if so, these tests show 
the superiority in this respect of the electrically formed 
alloy over that made by mixing pure aluminum in the 
ordinary manner. British firms are using the alloy, and no 
doubt its use will rapidly extend. Some of the best known 
steel founders are now employing it in England. 

Solders for Aluminum. 

Solders of all sorts are very useful, and consequently a 
knowledge of them will prove valuable. Space has been 
devoted under the head of " Formulas for Britannia 
Metal " to various methods of soldering in that metal. 

The first solder is one of the simplest and best for 
aluminum. Take suitable proportions of aluminum and tin, 
ii parts of the former and 45 of the latter. The metals 
must be melted separately. After this operation pour 



168 THE PRACTICAL ELECTROPLATER. 

them together, when they will be ready for casting into 
suitable strips or ingots. No flux is required in this opera- 
tion. 

For sheet aluminum an iron and tin solder may be used 
with a flux consisting of rosin, neutral chloride of zinc and 
grease. The metal should not be cleaned or scraped unless 
it is absolutely necessary to do so. In that case alcohol or 
essence of turpentine should be used for the purpose. For 

5 per cent, aluminum bronze tin solder may be used, but 
this is not possible with the 10 per cent, alloy, for which a 
preliminary copperplating is necessary. If it is difficult to dip 
the ends to be plated directly into the solution, blotting paper 
soaked in a solution CuSCK may be laid on them and a 
current passed. The above mentioned flux may be used. 

Another solder consists of 56 parts copper, 46 parts of 
zinc and 2 of tin, applied with borax. 

Pieces of cast aluminum bronze, in sand molds, can be 
joined together by running in some of the molten metal. 
If this operation is carried out properly the joint is indis- 
tinguishable from the remainder of the casting. Thin 
cylinders of aluminum are made in this way by bending the 
sheets round end to end and soldering with molten alumi- 
num. These formulas have been copyrighted by Munn 

6 Co. 

Matt Aluminum. 

In addition to the foregoing solutions the following 
method of imparting a matt silver appearance to metallic 
aluminum will be found of much value. The article to be 
matted is first immersed in about 10 to 15 per cent, warm 



TIN PLATING PROCESS. 169 

solution of caustic soda which has been saturated with 
common salt. The immersion should last for from fifteen 
to twenty seconds, which will be found long enough. The 
article must then be washed and brushed and immersed 
once more in the foregoing bath for about thirty seconds. 
Finally wash it and dry it in sawdust. It will then have 
the desired matt appearance. 



TIN PLATING PROCESS. 

Among the best, and at the same time the cheapest, 
substitutes for silver or a coating for tableware, kitchen 
utensils, &c, is pure tin, a method for detecting lead in 
which is given on another page. Tin costs less, but does 
not last as long as silver, and it is easily kept clean. 

There are many processes by which small goods of 
iron, brass, copper, &c, are plated with tin, among them 
the contact process, by which sheet tin or tinned sheet iron 
is made. 

If it is desired to tin hollow articles on the interior the 
metal must first be cleansed thoroughly by pickling it in 
dilute sulphuric acid or muriatic acid ; then scour the 
article w T ith fine sand. Heat over the fire to the melting 
point, sprinkle with powdered rosin and partly fill with 
melted pure grain tin which has been covered with rosin 
to prevent oxidation. Then turn and roll the vessel in 
all directions. This is done for the purpose of bringing 
the surface in contact with the metal in its molten con- 
dition. 



170 THE PRACTICAL ELECTROPLATER. 

After this has been done throw the greater part of the 
tin out and rub the surface with a tow brush to make the 
coating equal. The vessels must be heated sufficiently to 
keep the tin in them in a fused state. 

The amalgam process is seldom used nowadays, but 
consists in applying to the clean and dry metallic surface a 
film of pasty amalgam of tin with mercury, and then expos- 
ing the surface to heat, which volatilizes the mercury, leav- 
ing the tin adhering to the metal. 

A good formula for tinning by dipping is as follows : 

One and one-half ounces protochloride of tin. 
Thirteen pounds boiling water.. 
Eighteen ounces ammonia alum. 

The articles must be thoroughly cleansed and then 
placed in the hot solution until properly whitened. 




PLATINUM PLATING. 



"TN 1846 Mr. Roseleur, of Paris, discovered a process for 
Jf plating platinum and took out a patent thereon. This 
vA process proved very important and good results were 
obtained therefrom. Many scientists and workmen had 
made experiments in the same direction before him, but 
without satisfactory result. In 1847 Roseleur presented to 
King Louis Philippe a cup and plate on which were 
deposited by means of the electric current 400 grams of 
pure platinum, on which certain parts were left matt and 
others burnished. Around the cup was the following in- 
scription : " Premier vase platine a epaisseur, par Roseleur 
et Lanaux." (First cup thickly plated with platinum, by 
Roseleur and Lanaux.) 

For the following interesting account of the electro- 
deposition of platinum the author is indebted to Mr. 
William H. Wahl, of the Franklin Institute for the Promo- 
tion of the Mechanic Arts, Philadelphia. The permanence 
and unalterability of platinum — properties' which make it 
of inestimable value to the chemist — have suggested its 
application as a protective covering upon the surfaces of 
other metals, and, even in the early days of the art of electro- 
deposition, efforts to obtain a satisfactory coating of this 



172 THE PRACTICAL ELECTROPLATER. 

metal were made. The failure of these experiments served 
rather to stimulate than to deter subsequent investigators, 
and the problem has received the attention of a number of 
the most noted experts in the art. The results accomplished 
cannot be said to have been entirely satisfactory — a state- 
ment which will be fully sustained by the fact that electro- 
plating with platinum, on a commercial scale, is practiced 
to a very limited extent. When the wide field of applica- 
tion for platinum plating is considered — and there need be 
mentioned only philosophical, engineering, surgical, dental 
and electrical apparatus and instruments, firearms, watch 
cases and jewelry, to say nothing of the host of miscel- 
laneous articles of utility and ornament to which the metal 
could be advantageously applied — the conclusion is irresis- 
tible that the processes thus far proposed for the purpose 
do not fully meet the requirements of practical service. 

Thus far, of all the methods that have been proposed 
for electroplating with platinum three only appear to have 
sufficient merit to deserve special notice, which are : 

i. The Roseleur-Lanaux method, mentioned above, 
based on the electrolysis of a solution of the double phos-. 
phate of sodium and platinum. 

2. The process of the Bright Plating Company (of Lon- 
don, England), a modification of Roseleur's, involving the 
introduction into the bath of certain substances, such as 
sodium chloride and borax, to insure a bright deposit of the 
metal ; and 

3. Bottger's method, founded on the electrolysis of a 
solution of the double chloride of ammonium and platinum 
in sodium citrate. 



PLATINUM PLATING. 173 

Each of these baths will yield satisfactory results for a 
time. But the peculiar difficulties met with in the practice 
of platinum plating render it impossible to maintain the 
chemical integrity of these electrolytes, and in consequence 
they soon become inefficient or inoperative by reason of 
contamination with the secondary products formed therein. 

What follows gives the true explanation of the difficul- 
ties above referred to and indicates what, from a careful 
study of the subject, fortified by the results of numerous 
experiments, is the only feasible method of overcoming 
them. 

The first difficulty encountered is that of obtaining a 
bright, reguline and adherent deposit of the metal, in which 
form only it will answer the demands of practice. There is 
no difficulty in effecting the separation of the metal from 
solutions of almost any of its compounds. 

Zinc, iron and tin reduce it promptly by simple immer- 
sion, and this very facility of reduction is one of the reasons 
why, even by the method of electrolysis, the desired object 
is frequently accomplished only in an imperfect manner. 
For the electroplater is obliged to meet and overcome its 
obstinate disposition to separate from many of its com- 
pounds in the condition of platinum black, lacking coher- 
ence and adherence, and therefore entirely unsuited for his 
purpose. 

Another and no less serious difficulty arises from the 
insolubility of plates or sheets of this metal as anodes, when 
solutions containing platinum salts are submitted to elec- 
trolysis. In electroplating with copper, silver, gold and 
nickel but little difficulty is encountered in practice on this 



174 THE PRACTICAL ELECTROPLATER. 

account, since anodes of these metals are freely soluble in 
many solutions capable of depositing them when they are 
submitted to electrolysis, and the rate at which these anodes 
are respectively dissolved approximates so nearly to that at 
which the metals are deposited upon the objects at the 
cathode that the metallic strength of the electrolyte is 
maintained substantially uniform, and electroplating solu- 
tions of these metals may be operated for a long time with- 
out requiring additions of metallic salts. The electro- 
deposition of the metals whose anodes are thus tractable 
is carried on industrially with success. 

It results from this want of solubility of the anode 
that the metallic strength of the electrolyte employed is 
continuously being weakened, while the deposition of the 
metal is going on and the conductivity of the bath is being 
continually modified thereby. The character of the deposit- 
ing metal also is injuriously influenced by these constant 
alterations of condition in the bath. And, as the rate of 
deposition becomes slower and slower by reason of the 
gradual impoverishment of the metallic strength of the so- 
lution, it will be necessary to restore it by fresh additions 
of metallic salt. The practice in all the processes of elec- 
troplating with platinum employed up to the present, save 
that of Bottger, is to use for this purpose the tetrachloride 
of platinum. With this single exception, all the solutions 
for the electro-deposition of platinum thus far made known 
are made by treating the chloride with compounds of the 
alkalies, soda, potassa, or ammonia. Of these the phos- 
phates and oxalates of soda or potassa are in greatest favor, 
and a number of formulas for preparing platinum plating 



PLATINUM PLATING. 175 

baths with their aid have been described. The resulting 
substance is commonly a double salt, such, for example, as 
the double phosphate of sodium and platinum, the double 
oxalate of potassium and platinum, &c, contaminated, how- 
ever, in each case by the chloride of the alkali employed, 
which is formed from the decomposition of the platinic 
chloride. As often as it is found necessary to strengthen 
the bath, fresh additions are made of platinic chloride, 
which, by chemical interaction with the constituents of the 
bath, aided by the process of electrolysis, yields more alka- 
line chloride, and it follows that the bath, by reason of be- 
coming surcharged with this foreign substance, and with 
other secondary products of electrolytic decomposition, 
ceases to yield bright, reguline platinum upon the articles 
to be plated therewith and must be discarded. It then be- 
comes necessary to regain the platinum contained in the 
discarded bath, by one or another of several processes of 
reduction known to chemists. The platinum thus regained 
may be converted into chloride and utilized in the prepara- 
tion of a fresh bath, with which the same series of opera- 
tions will be repeated. Bottger purposes to maintain his 
bath by fresh additions of his original solutions, but it must 
be apparent that the continued electrolysis of such a solu- 
tion as he employs must be attended with the constant 
accumulation therein of alkaline chlorides from the same 
causes as those specified above. This rapid deterioration 
of the baths therefore involves their frequent renewal at 
the expense of time and labor, so that, in spite of the fact 
that there is a wide field for its application, it is principally 
for this reason that the art of electroplating with platinum 



176 THE PRACTICAL ELECTROPLATER. 

on a commercial scale is practiced only to a very limited 
extent. 

It occurred to Mr. Wahl that it might be practicable to 
overcome the principal difficulty set forth. Knowing the 
influence of extent of surface in promoting the solubility of 
substances, it appeared to him at least probable that if the 
platinum were exhibited at the anode in the form of plati- 
num black, or sponge, exposing thus an enormously greater 
number of points of attack to the electro-negative element 
or acid radical there set free, the result might be the solu- 
tion of the platinum, and the problem of maintaining the 
metallic strength of the electrolyte would thus be solved. 

The correctness of this conjecture was verified by ex- 
periment. For this purpose a plate of porous battery car- 
bon, previously treated with boiling hydrochloric and nitric 
acids, was saturated repeatedly with a solution of platinic 
chloride and dried. It was then introduced into a graphite 
crucible, finely divided carbon was packed about it, and the 
crucible and contents were heated for about half an hour to 
bright redness. The carbon plate then contained within 
its pores platinum in a state of eminently fine division. 
Treatment with water and with hydrochloric acid at boiling 
temperature failed to leach out any platinum salt, showing 
that the previous treatment had sufficed to reduce all the 
platinum salt to the metallic state. The carbon plate was 
then suspended as the anode in moderately diluted hydro- 
chloric acid, a platinum plate serving as the cathode The 
acid bath was gently heated and a current of moderate 
strength was allowed to flow through it. There was a lib- 
eral evolution of hydrogen from the cathode, and little per- 



PLATINUM PLATING. 177 

ceptible evolution from the anode. The acid solution 
gradually became colored from the formation of platinic 
chloride, and after some time the bright surface of the 
cathode began to blacken and ultimately became covered 
with a thick coating of platinum black. It was thus dem- 
onstrated that an anode of platinum in a fine state of 
division is readily soluble in an electrolyte which yields 
chlorine at the anode when the same is electrolyzed. « This 
observation is new. It proved, however, to have no prac- 
tical value, since the solution of the anode demanded the 
presence of a large proportion of free acid in the plating 
bath and the use of currents of such strength as to produce 
invariably the deposition on the surfaces to be plated of 
black and non-adherent metal. Furthermore, it was found, 
as was to have been anticipated, that the physical condition 
of the anode exerted no influence whatever in the electrol- 
ysis of baths formed of the oxy-salts of platinum, from 
which the best results in electroplating are obtained — since, 
in electrolyzing such compounds, the acid radical separated 
upon the surface of the platinum black failed to exert any 
perceptible solvent action. 

It was therefore necessary to devise some other plan 
for overcoming the difficulties herein described, and, after 
making a number of fruitless experiments, a plan was found 
which appeared to offer a solution of the troublesome prob- 
lem of electroplating with the group of metals whose anodes 
are insoluble, in a more satisfactory manner than any other 
that has hitherto been suggested. 

The plan referred to consists in employing platinum 
hydroxide for the purpose of maintaining the metallic 



178 THE PRACTICAL ELECTROPLATER. 

strength of the plating bath. For this purpose the hy- 
droxide, which is readily soluble in alkalies and in many of 
the acids, may be introduced into the plating bath from 
time to time and dissolved therein by stirring, or it may be 
permitted to remain in the bath in excess, the undissolved 
portion remaining at the bottom of the containing vessel, 
or it may be suspended in a canvas bag adjacent to or sur- 
rounding the anode of carbon, according as the nature of 
the electrolyte may indicate one or the other method to be 
the preferable one. As the solutions which yield the best 
results in plating are those of the oxygen salts, it was found 
advantageous also to prepare these directly from the hy- 
droxide. This method is capable of yielding a number of 
electrolytic baths of platinum that will maintain their me- 
tallic strength approximately unimpaired during electrol- 
ysis, and without the objectionable features of introducing 
into them substances that will cause them to deteriorate by 
the accumulation therein of injurious secondary products 
of decomposition, as is the case where such baths are 
maintained by additions of platinic chloride or alkaline 
chloro - platinates, as has hitherto been the invariable 
practice. Referring now specifically to the properties 
that render the platinic hydrate useful for the purposes 
indicated, the following points appear to be deserving 
of mention. 

It is readily soluble in aqueous solutions of the alkaline 
hydrates, and in a number of acids, mineral and vegetable. 
In the treatment of the platinic hydrate with aqueous solu- 
tions of the alkaline hydrates the former plays the part 
of a weak acid, forming compounds known as platinates, 



PLATINUM PLATING. 179 

which are very soluble, and from which the platinum is not 
precipitated on the addition of an excess of alkali. A 
weak aqueous solution of sodic or potassic hydrate (but 
especially the last named) will dissolve a large quantity of 
platinic hydrate at the ordinary temperature, though solu- 
tion takes place more freely when heat is applied. These 
solutions have the advantageous features of being freely 
conductive of electricity, and of yielding bright, reguline 
and adherent electro-deposits of platinum on metallic sur- 
faces previously prepared to accept the same. Further- 
more, with a current of moderate strength, the platinic 
hydrate only is affected, as shown by the pronounced evo- 
lution of oxygen at the anode and by the total absence of 
gas at the cathode. It is manifest also, from the free 
solubility of platinic hydrate in alkaline hydrate, even in 
the cold, that if free platinic hydrate is present in a bath 
of alkaline platinate, the alkali set free in the process of 
electrolysis will combine with this platinic hydrate to form 
fresh platinate. 

For this purpose it will be necessary either to have 
present in the bath at all times a small excess of platinic 
hydrate, which may remain upon the bottom of the contain- 
ing vessel without interference with the plating, and which 
may be replenished from time to time, or to introduce, at 
the end of the day's work, a quantity of the platinic 
hydrate sufficient to restore the metallic strength of the 
bath to normal, assisting the solution of the metallic 
hydrate by stirring, and, if necessary, by the application 
of gentle heat. 

As it was found that the platinate solutions act best 



180 THE PRACTICAL ELECTROPLATER. 

when they contain a considerable excess of free alkaline 
hydrate, being more conductive of the current and yielding 
the platinum more freely and in the best condition, the 
addition of the proper quantity of platinic hydrate at the 
close of the day's work in the case of a bath of considerable 
volume, or the addition of small quantities at intervals, in 
the case of a small bath, will be found to answer the de- 
sired purpose of maintaining the metallic strength of the 
bath approximately normal for an indefinite period. In a 
bath where considerable free alkali is present the platinic 
hydrate added as just indicated dissolves very freely even 
in the cold. 

The important fact is to be noted that the alkaline 
platinate solutions may be maintained and operated for a 
long time in the manner described, since no deleterious 
secondary products are formed by electrolysis to vitiate 
and render them inoperative, as will speedily be the case 
where the platinic chloride is used for this purpose. The 
mineral acids (hydrochloric, nitric, sulphuric and phosphoric 
acids) dissolved the hydroxide freely, as likewise do certain 
of the vegetable acids, notably oxalic acid, and form with 
corresponding salts of the alkalies double salts, many of 
which are soluble in water. 

Of the salts thus capable of being formed, however, so 
far as it was determined by experiment, only a limited num- 
ber appear to be adapted to yield a deposit of bright, regu- 
line and adherent platinum. The halogen compounds may 
obviously be prepared more conveniently by the direct 
solution of the metal in aqua regia than by the method de- 
scribed, but as the oxygen compounds of platinum yield 



PLATINUM PLATING. 181 

much more satisfactory results, they are excluded from 
consideration. 

Of the salts that may be formed from platinic hydrate 
by solution in acids (and in part by suitable combination 
with the corresponding alkaline compounds to form double 
salts), three only may be named as sufficiently useful to 
yield practically valuable results in plating. These are the 
phosphates, oxalates and acetates, of which also it is prac- 
ticable to form double salts with the alkalies, soda, potassa 
and ammonia, which yield bright, reguline and adherent 
plating. 

Oxalic acid, of all the oxygen acids, is the best solvent 
of platinic hydrate, dissolving it even in the cold, but with 
great energy when aided by heat and forming platinous ox- 
alate, with evolution of carbonic anhydride. From this 
brownish black or deep blue solution (according to concen- 
tration), brilliant reddish brown scales of the salt separate 
abundantly and readily from the hot saturated solution. 
A saturated aqueous solution of the simple oxalate pre- 
pared from the hydrate as above described will yield bright, 
reguline, adherent platinum when electrolyzed with a com- 
paratively weak current, with evolution of carbonic anhy- 
dride at the anode. With a stronger current hydrogen also 
appears at the cathode. This bath may be maintained 
indefinitely at normal metallic strength by observing the 
precaution to add oxalic acid and platinic hydrate in small 
quantities from time to time, or by keeping constantly at 
the bottom of the bath some platinic hydrate and adding 
oxalic acid in crystals or powder from time to time, as may 
be required to keep the bath saturated, or, what is much to 



182 THE PRACTICAL ELECTROPLATED 

be preferred, making a supply of platinous oxalate from 
platinic hydrate in the manner previously described and 
keeping an excess of this present in the bath at all times. 
This bath has the same advantages as are possessed by the 
alkaline platinate baths described above, that is, of being 
capable of indefinite maintenance at normal metallic 
strength and of introducing no substances that will cause 
its deterioration by the formation of secondary decomposi- 
tion products. 

Phosphoric acid also is a solvent of platinic hydrate. 
A dilute aqueous solution of this acid will dissolve a small 
quantity of the metallic hydrate in the cold, and a much 
larger quantity when aided by heat. With increasing con- 
centration, the solvent power of this acid for platinic 
hydrate is correspondingly increased. The resulting solu- 
tion of phosphate of platinum, according to the degree of 
concentration, will be wine yellow to cherry red in color, 
and with a comparatively weak current will yield bright, 
reguline and adherent platinum on the metallic surfaces 
properly prepared to accept the same. The electrolysis 
of this compound also does not involve the formation of 
deleterious secondary products, the result of the operation 
being the separation of the metal at the cathode, and of the 
acid radical at the anode — and of the elements of water 
which are evolved as gases respectively from anode and 
cathode. In the operation of the bath, therefore, it will be- 
come more and more acid as the metal is withdrawn by 
the accumulation therein of the phosphoric acid set free at 
the anode. The maintenance of the metallic strength of 
the bath may therefore be effected, as in the foregoing cases, 



PLATINUM PLATING. 183 

by having present at all times a small quantity of platinic 
hydrate or by the addition at the end of each day's work 
of the quantity of the metallic hydrate required to re- 
store the amount of metal withdrawn. This bath must be 
worked very acid, and the solution of the platinic hydrate 
to maintain the strength of the bath must be facilitated by 
heating, as the solvent power of phosphoric acid for platinic 
hydrate is much inferior to that of oxalic acid. The double 
phosphates of platinum with certain of the alkalies may be 
formed, which will be capable of yielding a deposit of 
bright, reguline and adherent metal, and of being main- 
tained approximately at normal metallic strength in the 
same manner as set forth above. The best results were 
obtained with the ammonio-platinic phosphate, prepared 
by adding to the solution of platinic hydrate in phosphoric 
acid sufficient aqua ammoniae to cause the same to give an 
alkaline reaction, which point will be indicated by the for- 
mation of a grayish precipitate that will not disappear on 
stirring ; then restoring the acidity of the solution by add- 
ing free phosphoric acid in excess, upon which the precipi- 
tate readily dissolves. The resulting solution is yellowish 
or brownish and yields superb plating, though, on account 
of the greater difficulty of maintaining its metallic strength 
by the solution of hydroxide, it is not so well adapted as 
the oxalate for the work of electro-deposition on the large 
scale. The sodio-platinic phosphate, formed in a manner 
precisely analogous to the ammonia compound just de- 
scribed, will also yield bright, reguline and adherent 
plating, but the soda salt is less freely soluble than the 
corresponding ammonia compound, and consequently more 



184 THE PRACTICAL ELECTROPLATER. 

difficult than the latter to maintain of normal metallic 
strength. 

Platinic hydrate is only very sparingly soluble in 
strong acetic acid, and it is impracticable to facilitate the 
solution by boiling, since by persisting in this for a very 
short time the hydrate is decomposed and black platinic 
oxide formed, which is quite insoluble in this menstruum. 
An alkaline acetate bath may be prepared by the addition 
to the alkaline platinates above described of as much ace- 
tic acid as may be introduced without causing the forma- 
tion of a permanent precipitate. But although the ap- 
pearance and quality of the plating obtained with this bath 
leave nothing to be desired, the bath does not meet the 
requirements in respect of indefinite maintenance in nor- 
mal metallic strength and uniform composition. This 
difficulty, however, becomes less and less pronounced as 
the bath is made more strongly alkaline, when it approxi- 
mates more and more closely to the alkaline platinates, for 
it is obvious that in the presence of a large amount of free 
alkali this would unite with the acetic acid to form a sim- 
ple acetate. The resulting solution would no longer con- 
tain sodio-(potassio-) platinic acetate, but sodic (potassic) 
acetate, sodic (potassic) platinate and free alkali. Never- 
theless, the presence of acetic acid in such alkaline bath ap- 
pears favorably to influence the quality of the plating yielded, 
giving the deposited metal a whiteness approaching that of 
silver, and since, furthermore, acetic acid yields only the 
elements of water and volatile compounds, when electro- 
lyzed, and therefore does not contaminate the electrolytic 
bath by forming deleterious secondary products, its judicious 



PREPARING ELECTROPLATING BATHS. 185 

addition to the above described alkaline platinate baths 
was found to present some advantages. 

The foregoing comprise the compounds found to yield 
the most satisfactory results in platinum plating. 

Directions for the preparation of the several electro- 
lytic baths above described are appended, and indicate the 
most favorable conditions for working them. 

Prof. Wm. L. Dudley, of Vanderbilt University, Nash- 
ville, Tenn., has independently worked out the problem 
of electroplating with iridium in a manner precisely 
analogous to that herein described with platinum. Professor 
Dudley employed the following procedure : " A bath of the 
metal may be composed of either the chloride (IrCl 4 ), the 
double chloride of iridium and sodium, a double sulphate 
of iridium-ammonium. The latter was preferred. The 
bath was kept saturated with metal by suspending canvas 
bags in the solution (either near to or around the anodes) 
containing the hydroxide of iridium." 

Directions for Preparing the Electroplating 

Baths. 

For the alkaline platinate bath the following directions 

may suffice : 

Two ounces platinic hydrate. 

Eight ounces caustic potassa (or soda). 

One gallon distilled water. 

Dissolve half of the caustic potassa in a quart of dis- 
tilled water ; add to this the platinic hydrate in small 
quantity at a time, facilitating, solution by stirring with a 
glass rod. When solution is effected stir in the other half 



186 THE PRACTICAL ELECTROPLATER. 

of alkali, dissolved in a quart of water, then dilute with 
enough distilled water to form a gallon of solution. To 
hasten solution the caustic alkali may be gently heated, 
but this is not necessary, as the platinic hydrate dissolves 
very freely. This solution should be worked with a current 
of about two volts and will yield metal of an almost silvery 
whiteness upon polished surfaces of copper and brass, and 
quite freely. There should be slight, if any, perceptible 
evolution of hydrogen at the cathode, but a liberal evolu- 
tion of oxygen at the anode. The addition of a small pro- 
portion of acetic acid to this bath improves its operation 
where a heavy deposit is desired. The anode may be of 
platinum or carbon, and owing to the readiness with which 
the metal is deposited an excess of anode surface is to be 
avoided. Articles of steel, nickel, tin, zinc or german silver 
will be coated with black and more or less non-adherent 
platinum, but by giving objects of these metals a prelimi- 
nary thin electro-deposit of copper in the hot cyanide bath 
they may be electroplatinized in the alkaline platinate bath 
equally as well as copper. The bath may be worked hot 
or cold, but it is recommended to work it at a temperature 
not exceeding ioo° Fahr. It may be diluted to half the 
strength indicated in the formula and still yield excellent 
results. The surface of the objects should be highly pol- 
ished by buffing or otherwise, prior to the introduction 
in the bath, if the resulting deposit is designed to be 
brilliant. 

The deposition of platinum takes place promptly. In 
five minutes a sufficiently heavy coating will be obtained 
for most purposes. The deposited metal is so soft, however, 



PREPARING ELECTROPLATING BATHS. 187 

that it requires to be buffed very lightly. A heavier 
deposit will appear gray in color, but will accept the 
characteristic lustre of platinum beneath the burnisher. 

The oxalate solution is prepared by dissolving an ounce 
of platinic hydrate in 4 ounces of oxalic acid and diluting 
the solution to the volume of a gallon with distilled 
water. The solution should be kept acidified by the 
occasional addition of some oxalic acid. The simplest 
plan of using this bath, and which requires no attention 
to proportions, is simply to work with a saturated solu- 
tion of the oxalate, keeping an undissolved excess always 
present at the bottom of the vessel. An addition of a 
small quantity of oxalic acid now and again will be found 
advantageous. The double salts of oxalic acid with plat- 
inum and the alkalies may be formed by saturating the 
oxalate of the desired alkali with platinic hydrate and main- 
taining the bath in normal metallic strength by the presence 
of an undissolved residuum of platinous oxalate. 

The double oxalates are not so soluble in water as the 
simple salt. The oxalate baths, both of single and double 
salts, may be worked cold or hot (though not to exceed 150 
Fahr.) with a current of comparatively low pressure. The 
metal will deposit bright, reguline and adherent on copper 
and brass. Other metallic objects must receive a prelim- 
inary coppering as above. The deposited metal is dense, 
with a steely appearance, and can be obtained of any de- 
sired thickness. 

The deposit obtained in the oxalate baths is sensibly 
harder than that from the alkaline platinate bath, and will 
bear buffing tolerably well. 



188 THE PRACTICAL ELECTROPLATER. 

The phosphate bath may be prepared by the following 

formula : 

Eight ounces phosphoric acid, sirupy (sp. gr. 1.7). 
One to one and a half ounces platinic hydrate. 
One gallon distilled water. 

The acid should be moderately diluted with distilled 
water and the solution of the hydrate effected at the boiling 
temperature. Water should be added cautiously from time 
to time to supply that lost by evaporation. When solution 
has taken place the same should be diluted with sufficient 
water to make the volume one gallon. The solution may 
be worked cold or warm to ioo° Fahr., and with a current 
much stronger than that required for the platinates and 
oxalates. The ammonio- (and sodio-) platinic phosphates 
may be formed from the simple phosphate by carefully 
neutralizing the solution of the phosphate with ammonia (or 
soda); then adding an excess of phosphoric acid, or enough 
to dissolve the precipitate formed, and an additional quan- 
tity to insure a moderate amount of free phosphoric acid 
in the bath. The phosphate baths will be maintained of 
normal strength by additions of platinic hydrate, the solu- 
tions of which will have to be assisted by heating the bath, 
preferably at the close of each day's work. The metal 
yielded by the electrolysis of these phosphate solutions is 
brilliant and adherent. It has the same steely appearance 
as that exhibited by the oxalate solutions, but to a less pro- 
nounced degree. The physical properties of the deposited 
metal are in other respects like those described in connec- 
tion with that obtained from the oxalate baths. 



CADMIUM AND SILVER ALLOY 
PLATING. 



~"1g)T has always been held by those who view alloys as 
X true chemical compounds that the fact that certain 
vl, of them can be deposited electrically upholds their 
position. Seeing that brass was almost the only alloy of 
which the deposition was successfully practiced, the position 
lacked strength, owing to the scanty evidence supporting 
it. The process of plating patented by the London Metal- 
lurgical Plating Company, under the name of " Areas," has 
gone through several stages of development, and in its 
newest form presents several interesting features. Cad- 
mium — the use of which has been confined to the produc- 
tion of artists' pigment, to the formation of fusible alloys 
and to the aid of the photographer — which is similar to zinc, 
and associated with it in its ores, has been made to do duty 
in a larger field. Instead of the zinc and silver alloy first 
chosen for "Areas" plating, one containing cadmium is pre- 
ferred. At first sight the change would seem to be for the 
worse, as cadmium is about twelve times the price of zinc. 
But, as silver is more than twelve times the price of cad- 
mium, the fact that an alloy containing only two-thirds of 



I go 



THE PRACTICAL ELECTROPLATER. 



the silver previously necessary can be used turns the 
balance of advantage in the other direction. In the origi- 
nal "Areas" alloy, 90 per cent, of silver and 10 of zinc 
were used, while in the latest substitute the proportions are 
about 65 per cent, of silver and 35 of cadmium. 

Other alloys may be used for special purposes, notably 
when cheapness is the first consideration, and the percent- 
age of cadmium then increased to as much as 90 per cent. 




Plating Tank for Cadmium and Silver Alloy. 



Alloys which contain rather more than 40 per cent, of cad- 
mium are difficult to deal with, on account of being liable 
to split during rolling. The appearance of a rolled anode 
in which this has happened is illustrated on the follow- 
ing page, the lines of cleavage being very curious in their 
regularity. It is not easy to see what can be the cause of 
the fissures, but it is probable that some segregation of the 
constituent metals from top to bottom of the plate must take 
place, as alternate strips differ slightly, but appreciably, in 
color. The rolling of the other alloys can be done without 



CADMIUM AND SILVER ALLOY PLATING, 191 

difficulty, and, as is usual in electroplating, rolled anodes 
are preferred to cast. Another working difficulty was met 
with and surmounted. It consisted in the tendency dis- 
played by the electrolyte to cut through the anodes at the 
point where they entered the liquid. This was overcome by 
the following means : In the plating tank the electrodes are 
suspended on a frame resting on the edge of the bath. 
This frame has rollers which run on the tank edge and 
short inclines thereon. The frame is connected by a rod 
from an eccentric turning on a shaft which runs from end 
to end of each set of tanks. By the two motions thus ob- 




A Split Rolled Anode. 

tained the tray oscillates horizontally through a stroke of 
about 2^/2, inches, and simultaneously has a vertical move- 
ment of about three-quarters of an inch. By this means the 
lighter liquor, poorer in metal and richer in the non-metallic 
radical, is prevented from collecting at the top and attack- 
ing the anode unduly at that point, and the uniformity of 
the bath is secured. The baths are usually worked cold, 
and are composed of the cyanides of silver and cadmium 
dissolved in excess of potassium cyanide. Plating by this 
method is as brilliant and of as good a color as silver in 
appearance, and is said not to tarnish with sulphurous gases 
in the manner characteristic of that metal. By varying the 



1 92 THE PRACTICAL ELECTROPLATER. 

conditions of deposition suitably, a bright coating can be 
obtained, and burnishing thus saved, a noteworthy ad- 
vantage for cheap goods plated too thinly to stand much 
polishing. 

There are many processes nowadays for silver alloy 
plating by electrolysis, and among them is that here given. 
An alloy of silver which contains about 25 to 30 per cent, 
of cadmium is used. If, however, a cheaper plating is 
wanted, from 40 to 90 per cent, of cadmium will be found 
suitable. To make the bath, dissolve cyanide of cadmium 
in a solution of cyanide of potassium, forming a double salt 
which has a slight excess of potassium cyanide. A small 
quantity of the double salt of the cyanides of potassium 
and silver must be added to the solution, the two together 
forming the electro-depositing bath. The anode should be 
formed of an alloy of silver and cadmium in the same pro- 
portions or nearly the same, as are desired in the alloy to be 
deposited. 




ELECTROTYPING. 




^=^HE electrotyping art has assumed considerable 
proportions, with the prospect of a still more 
vigorous growth. Having in mind the im- 
portance of this branch of trade the author secured the 
services of one of the best known electrotypers in the 
United States for the production of the following article 
on electrotyping, Mr. P. M. Furlong, formerly superintend- 
ent of the electrotyping department of the Government 
Printing Office, Washington, D. C, and now head of the 
electrotyping foundry of the celebrated De Vinne Press, 
New York. Mr. Furlong has acquired much renown in 
electrotyping circles, his name being associated with 
several notable inventions and improvements in this art. 
From the foregoing the reader will be able to gauge the 
value of the article here printed. 

As applied to plate printing electrotyping consists in 
the molding or reproducing of printing surfaces by means 
of a plastic material, and the deposition of a copper shell 
thereon, by separating the metal from the solution and 
depositing the same in solid form by means of a galvanic 
or electric current. The shell which results is removed 



ELECTROTYPING. 



195 



from the mold and backed with a suitable metal, after 
which it is finished, ready for the printer. 

Much as the world is indebted to European scientists 
for many of the earlier discoveries in this process the credit 




Case Filling Table. 

of its practical application to printing purposes belongs to 
the electrotypers of the United States. Their ingenuity 
and skill, and the application of labor saving machinery 
and appliances, have brought the art to its present degree 
of perfection. 



196 



THE PRACTICAL ELECTROPLATER. 



The process has been so much improved in the past 
few years that it is found more economical, in printing 
large editions, to electrotype the forms when made up than 
to wear out the type on the press. This statement holds 




Molding or Toggle Press. 

good in regard to complicated jobs, blanks, tables, &c, 

which otherwise would have to be laid aside for future use. 

The saving of time, material and money by having an 

electrotype foundry attached to an office is beyond ques- 



THE FOUNDRY. 197 

tion, as it enables the printer to duplicate his forms rapid- 
ly and distribute the type without delay. It also enables 
him to dispense with a great amount of expensive material, 
which otherwise would be in constant use and wear. Econ- 
omy in presswork is important and should not be over- 
looked, particularly for long runs, as the forms may be 
duplicated at a trifling expense above the cost of composi- 
tion, reducing the number of impressions to a minimum, 
and thereby increasing the profit on the work. Should the 
plates get damaged in any way, or corrections or alterations 
become necessary, they can be attended to at once on the 
premises, avoiding expensive delays caused by having the 
work done outside. Finally, a sharper and cleaner impres- 
sion is obtained from a copper surface than is possible 
from either type or stereotype metal. 

In what follows will be found a detailed and practical 
description of the best methods and latest improved ap- 
pliances necessary to carry on electrotyping successfully. 

The Foundry. 

Electrotype foundries should preferably be located on 
top floors, so as to secure plenty of light and ventilation. 
When electrotyping is carried on extensively it will be 
advisable to have two rooms — a molding room and a 
finishing room. The former should be well ventilated, 
have a high ceiling, a concreted floor and a plentiful supply 
of water, and contain the appliances for melting wax, pre- 
paring and taking molds, and depositing shells and back- 
ing them for the finisher. The finishing room should have 




Blackleading Machine. 



TO THE PRINTER. i 99 

plenty of light, and contain all the material necessary for 
finishing, mounting and repairing the plates. 

To the Printer. 

All quadrats, leads and furniture should be high, if 
possible. Low material is used in offices having no high 
quads, &c; but greater care is necessary and more time 




Electrotype Furnace. 

consumed in cutting down the displaced wax on the mold. 
More labor is also required on the electrotypes, and the 
plates are not so perfect as when high material is used. 

White and copper faced type should not be used in the 
same form, as the deposit of copper on the type, be it ever 



zoo THE PRACTICAL ELECTROPLATER. 

so thin, thickens the fine lines and causes a variation in 
their height, which is sure to be reproduced in the plate. 

The process of copperfacing type differs from that of 
electrotyping in a very important point. In the electro- 



Electrotyper's Saw. 

type the atoms of copper attach themselves to and dupli- 
cate the smooth face of the mold, and this smooth faced 
duplicate becomes the printing surface. But in copper- 



TO THE PRINTER. 201 

facing these atoms attach themselves to the smooth sur- 
face of the types and adhere thereto, leaving the rough, 
granular upper side of the deposit as the printing surface. 

When the matter occupies only a portion of a page, or 
the lines are shorter than its full width, as in poetry, an in- 
verted letter should be placed in each corner as a guide to 
the finisher in beveling the plate. All large blanks, title 
pages and unprotected lines should have inverted letters so 
placed as to protect the exposed lines from injury while 
the plate is being shaved. 

Owing to the immense strain on the form in the oper- 
ation of molding, it is necessary, in order to bind the type 
securely, that the chase and furniture should be three- 
quarters of an inch high and perfectly true and square. 
The form must be properly justified and every type should 
be squarely on its feet. Use plenty of quoins, and lock 
the form much tighter than for letterpress, otherwise the 
displacement caused by wax entering between the type will 
spread the lines in both form and mold. In consequence 
of this the type will be thrown off its feet and an imperfect 
plate will be the result, besides the annoyance of having 
to scrape the wax from the type. 

When the types are placed in the chase they should be 
surrounded by type high guards, shaved perfectly true, 
with the shoulder toward the type. These guards prevent 
the wax from spreading during the molding operation ; 
they facilitate the process of backing the shell ; protect the 
plate while being shaved, and are finally cut down and used 
as bevels, by which means the plate is clamped to the pat- 
ent block. 



202 THE PRACTICAL ELECTROPLATER. 

Should the spaces or leads rise to the surface of the 
type while the form is being planed down, it is a sure indi- 




Power Shaving Machine. 



cation that either the matter is not perfectly justified or 
the rules or guards bind. 



WOOD CUTS. 203 

All imperfect letters should be marked by the proof 
reader and changed before the form is sent to the foun- 
dry, as the plate will be an exact duplicate of the type. 
This is important, especially to printers who do their own 
electrotyping, as the imperfect letters, unless discarded, 
will continually reappear and be the means of causing un- 
necessary labor and expense by inserting good type to re- 
place the damaged ones in the plate. 

It is absolutely necessary that the form should be 
locked up perfectly square, otherwise the plate will be out 
of true when trimmed or beveled — the result of which will 
be an imperfect register on the press, and consequently a 
crooked appearing page or job. 

Wood Cuts. 

Wood cuts should be surrounded by type high guards 
and locked up in the same manner as type forms, in order 
to prevent the blocks from cracking. The guards also pre- 
vent the wax from spreading and causing a heavy edge 
around the outside of the mold. The cuts should be care- 
fully cleaned with ammonia or benzine and thoroughly 
dried before being blackleaded. Never use lye, as it opens 
the joints and swells the lines of the engravings. 

Should fine checks or cracks appear on the face of a 
wood cut to be molded, place a strip of moist blotting 
paper about an inch wide over the crack and apply a heated 
building iron to the blotting paper for a few seconds or un- 
til the paper becomes partly dry, when the check will close 
or disappear. Rub the cut dry immediately with a brush, 



204 THE PRACTICAL ELECTROPLATER. 

and blacklead and mold at once, as the crack may reap- 
pear. 

When cuts and type are used in the same form, the 
former should be perfectly true and square and mounted on 
metal, otherwise the type will be thrown off its feet. When 
cuts are too high, they should be reduced to the height of 
the types ; if too low, they should be made type high by 
proper underlaying. 

Molding from Duplicates. 

Every remove from the original means an inferior 
plate, to avoid which never use stereotypes or electrotypes 
to duplicate from, if possible, as a much better mold can be 
made from the wood cut or the original. 

Molding from Plates Mounted on Wood. 

Plates mounted on wooden bases, when used in type 
forms from which electrotypes are to be made, are a source 
of much annoyance to the molder and finisher, as the 
wooden base gives way or sinks below the type in the mold- 
ing process, and in consequence the finisher is obliged to 
beat up the cut from the back to a true and even surface 
with the face of the plate, or the cut must be sawed out 
and resoldered in the plate. This involves a waste of time 
and adds considerable unnecessary expense to the cost of 
the work ; and even when carefully done by an expert the 
fine lines are distorted and the plate often destroyed. The 
details of process cuts or half tones are often lost in mold- 
ing by being mounted on wooden bases. 



MOLDING COMPOSITION. 205 

Too much cannot be said in regard to this matter, as 
pressmen are often censured for defects in printing that are 
sometimes due to imperfect molding and finishing. In 
order to remedy this evil, or at least place the blame where 
it properly belongs, the pressman should be supplied with a 
good handpress proof from the original before the impres- 
sion is taken in the wax. 

If plates are used in forms from which electrotypes are 
to be made, they should be mounted on solid metal bases. 
The cost is trifling as compared with the results. 

Molding Composition. 

New molding composition consists of about 85 per 
cent, of pure beeswax, 10 per cent, of crude or virgin tur- 
pentine and 5 per cent, of plumbago, which should be 
thoroughly mixed and freed from moisture (before being 
used) by boiling for about two hours in a jacketed steam 
pot. Five per cent, of burgundy pitch should be added to 
the above in very hot weather. The crude turpentine is 
added to reduce the cone-like structure of the wax, and the 
blacklead to prevent the composition from sticking to the 
cuts or form, while the burgundy pitch prevents the com- 
position from becoming too soft in warm weather. 

Beeswax is obtained by slicing the comb taken from 
the hive, draining and afterward expressing the honey, and 
melting the residue in boiling water, which is kept hot for 
some time, in order to allow the impurities to separate and 
be dissolved. When the liquid cools, the wax concretes and 
is then placed in pans or other suitable vessels. In this 
state it has a yellowish color and is of a firm, solid consis- 



206 THE PRACTICAL ELECTROPLATER. 

tency and somewhat brittle. Pure beeswax has a granular 
structure, and when rubbed with the thumb (when the 
thumb is perfectly dry) emits a slight squeaking noise. 
Its point of fusion is 142 Fahr., and its specific gravity 



Electrotype Trimmer. 



from .960 to .965. Various adulterations have been prac- 
ticed, most of which may be detected. Meal, earth and 
other insoluble substances are separated by melting and 
straining the wax. When the fracture is smooth and shin- 



THE MOLDING CASE. 207 

ing, instead of granular, the presence of rosin may be sus- 
pected ; this is dissolved by cold alcohol, while the wax is 
left untouched. Chloroform will dissolve only 25 per cent, 
of pure wax, while stearine and fatty matters are dissolved 
completely. Spermaceti, lard, oil, tallow and suet reduce 
the melting point and specific gravity, and also render the 
wax softer and less cohesive. They also produce a smooth 
and less granular fracture. 

Pressmen frequently find they cannot successfully print 
plated papers in bronze. The heavy coating on the paper 
absorbs the size, so that the bronze will not stick. This can 
be obviated by running the sheets twice through the press, 
using size each time and allowing it to dry after the first 
impression, which it will do very quickly. The first print- 
ing fills up the pores in the paper, leaving an excellent 
ground for the second impression, to which the bronze will 
adhere firmly. The extra cost of the double working should 
of course be taken into consideration in estimating the ex- 
pense of the work. 

The Molding Case. 

Some molders use a brass molding case with a rim 
about an eighth of an inch deep, while the modern method 
is to mold in a flat or rimless case. The latter is superior 
to the old method both as regards economy and results, as 
the flat case can be cast at a trifling cost from electrotype 
metal in use in the foundry, and can be shaved to the de- 
sired thickness. on the ordinary shaving machine. Should 
the flat case get out of true or become damaged in any way, 




Routing Machine. 



SHAVING THE WAX CASE. 209 

it may be thrown back into the metal pot and a new case 
cast at leisure. 

Filling the Case. 

The molding case, having been slightly warmed, is 
placed on a level iron table and surrounded by guards 
about an eighth of an inch higher than the case. The wax 
is now poured on the case with a warm ladle through a fine 
sieve, in order to prevent the wax from chilling and also to 
keep out any foreign substances that may have fallen into 
the wax pot. The operator immediately draws a gas flame 
or a heated round iron rod slowly over the wax to wipe off 
the air bubbles that rise to the surface. If the water is not 
thoroughly boiled out of the wax, a heated building iron or 
gas flame is passed over its surface, in order to evaporate 
any remaining moisture. After the wax has set, but while 
still warm, the guards should be relieved from the sides of 
the case, and all adhering wax scraped therefrom, that 
they may be ready for immediate or future use. Should 
the wax shrink away from the sides of the case, or crack 
while cooling, throw it back into the wax pot and add 5 per 
cent, of crude or virgin turpentine, stirring for about five 
minutes, and proceed as before. 

Shaving the Wax Case. 

When the wax is cold it may be shaved to any de- 
sired thickness on a shaving machine used expressly for the 
purpose. This insures a true and even case, and the result 
is that a true and even impression is obtained with less 



210 THE PRACTICAL ELECTROPLATER. 

strain on the press and less labor for the molder than is 
possible when the case is not shaved. 

Blackleading the Case before Molding. 

After the case has been shaved it is carefully black- 
leaded by means of a goat or badger hair brush used for 
that purpose. A cleaner and more economical method is 
to mix a solution of plumbago and water to the consistency 
of cream in a large bowl and rub the solution carefully and 
evenly with a soft sponge over the surface of the wax, 
which should be rubbed dry with the palm of the hand be- 
fore the mold is taken. 

Graphite. 

Graphite and plumbago, more commonly called black- 
lead, are different terms for the same substance. Graphite 
does not contain a trace of lead, and only occasionally a 
slight trace of iron, which is foreign to it. 

Graphite is one of two forms — the other being the 
diamond — in which carbon appears in nature. It is not af- 
fected by any chemical compound and is also not affected 
by heat, except at very high temperatures, when it slowly 
combines with oxygen. It occurs either in mica-like scales 
scattered through rock or in a powder disseminated through 
clay or in solid masses like coal. 

These three kinds are very different in appearance. The 
first, after being separated from the rock in which it occurs, 
resembles, except in color, flakes of bran. This variety is 
found principally in the United States, by far the larger 



GRAPHITE. 211 

portion being produced at Ticonderoga, N. Y. The second 
variety is found in clay beds in Austria-Hungary and Ger- 




Plate Beveling Machine. 



many. The third variety comes from Ceylon, where it fre- 
quently occurs in large masses like coal and is mined in 
a crude manner by the Singhalese, often containing as high 



212 THE PRACTICAL ELECTROPLATER. 

as 95 percent, of pure graphite. Pure graphite is the soft- 
est and is selected especially for the use of electrotypers. 
The American and Ceylon forms show a silvery black color 
and are very slipped and soft to the touch. . The German 
form is dead black in color and acquires a polish only by 
rubbing. 

The usual trade test for graphite is to place a spoonful 
in the mouth. Clay, if present, will cause the sample to stick 
to the tongue ; soapstone and slate are recognized by 
their taste, while the finest particles of silica are felt be- 
tween the teeth. 

Washing the Form. 

■ After the form is laid on the stone the operator removes 
all ink from the face of the type and cuts by means of 
benzine and a stiff brush, and when thoroughly dried the 
form is planed down. In the meantime the molder must be 
careful to observe that all the types are squarely on their 
feet and that all spaces, quadrats and leads are pushed back 
in their proper places. 

Blackleading the Form. 

Plumbago is now rubbed into the form by means of a 
moderately stiff brush, particular attention being paid to 
blackleading the sides of the rules and types. See also 
that the plumbago penetrates every crevice, in order to 
prevent the wax from sticking to the form. If this opera- 
tion is carefully performed the form will relieve freely from 
the wax and when held to the light will present a smooth 
and polished surface on the face and sides of the mold. 



CONCAVE IN TYPE. 213 

Great care must be taken that no blacklead clogs the fine 
lines of engravings, as much depends on the preparation of 
cuts for molding. 

Before the forms are returned to the printer all plum- 
bago and wax should be removed by means of hot lye and 
a stiff brush, after which they should be rinsed with run- 
ning water by means of a hose. Clean forms containing 
wood cuts with benzine. 

Concave in Type. 

Concave is a constant source of annoyance to electro- 
typers and printers. Several theories have been advanced 
as to its cause, but the difficulty still remains to annoy 
those molders who have not discovered a remedy for this 
source of annoyance. 

The custom of running sufficient cases in advance to 
last for several hours or during the day is a good one, 
provided the wax is kept in proper condition for molding ; 
but generally the wax becomes cold and hardens before 
the cases are needed, and the molder loses much valuable 
time in reheating wax from the back of the case, after 
which he places the cold form on the face of the wax and 
takes the impression, the result being of concave mold and 
consequently a concave surface on the face of the electro- 
type. 

In order to avoid concave and have the face of the 
plate as true and sharp as the original, first shave the mold- 
ing composition to an eighth of an inch thick, and then 
place a sufficient number of cases for immediate use in a 
steam heated box, which should be kept at a uniform 



214 THE PRACTICAL ELECTROPLATER. 

temperature until needed. When the wax is warm enough 
on the face to take an impression of the thumb, blacklead 
the wax, and mold the form to the shoulder of the type. 

If it becomes necessary to reheat the case do so 
thoroughly, or until it is quite warm, and then cool it from 
the back, as the metal case, being a better conductor, re- 
tains the heat much longer than the wax. Hence the wax 
is softest nearer the metal. If good results are expected 
this must be reversed. Or in other words the surface of 
the composition must be softer than that portion nearer 
the metal case. 

Molding the Form. 

The form, if large, is placed on the projecting table of 
the molding press, and the warmed wax case, previously 
polished with plumbago, is placed thereon ; a stiff book- 
binder's board, about an eighth of an inch thick, cut to the 
size of the bed of the press, is then placed on the back of 
the case in order to retain the proper temperature in the 
wax while the molds are being taken. 

In molding small forms or cuts the case is laid on a 
bookbinder's board on the projecting table of the molding 
press, and the form or cut placed face down thereon. The 
form and case are now slid under the head of the press and 
molded in quick succession, being careful to blacklead the 
form or cut before each impression. 

When electrotype or process cuts are to be duplicated, 
or plates and types are used in the same form, it has been 
found almost impossible to make a perfect mold in the first 
impression. In order to produce the desired results, spread 



m- 




Combined Jig Saw and Drill. 



216 THE PRACTICAL ELECTROPLATER. 

(with a separate brush) a thin film of Crocus martis care- 
fully and evenly over the blackened film on the surface of 
the wax ; or the Crocus may be rubbed into cuts instead of 
on the wax, with equally good results. The form and case 
are now slid under the head and centre of the press, and 
sufficient hand or steam power applied to force the wax to 
the shoulder of the type. Should the wax stick to the form 
in molding, pry the case gently at both ends with a screw- 
driver or similar tool, and then lift it squarely from the 
form ; otherwise there is a liability to tear the wax from 
between the type or to distort the sides of the mold. 

Cutting Down the Mold. 

The mold is now examined to see if a perfect impres- 
sion is obtained, and, if satisfactory, the displaced wax is cut 
down to the type shoulder. This is best performed by 
means of a sheath knife with a blade about 8 inches long, 
bent on an angle to elevate the handle, and sharpened on 
the under or beveled side to a keen edge. 

The cutting down of the displaced wax on the mold is 
done in the following manner : The operator, after seeing 
that the mold is slightly warm, lays the case on a level table 
in front of him, and while holding the cutting tool in the 
right hand heats it over a gas flame, and after laying the 
tool on its edge quickly cuts the displacement from around 
the sides of the mold. The tool is again heated, and the 
operator, with a quick swinging motion, cuts diagonally 
across the mold, with a slight upward tendency toward the 
end of the cut, being careful to hold the knife firmly with 
the right hand and to guide the blade on its bevel with the 



BURNING DOWN THE MOLD. 217 

fingers of the left hand, in order to prevent the tool from 
digging into the wax. The cutting tool should have a keen 
edge and be repeatedly heated over a gas flame, otherwise 
a film of wax will form over the openings to the rules or 
bowls of the type, which, if allowed to remain, would pre- 
vent the cavities of the mold from being properly black- 
leaded. 

Cutting down the mold is a difficult operation for the 
beginner, and considerable practice is necessary before 




Rotary Force Pump. 

perfection is attained. This operation is unnecessary, if the 
impression is taken from a high spaced form. 

After the displaced wax is cut down, the operator 
should look carefully over the work, and with a needle or 
other pointed tool pick out any wax that may have been 
forced into the rules or the cups of the letters. 

Burning Down the Mold. 

Burning down the mold is performed by attaching to 
a gas pipe a sufficient length of rubber tubing, having a 



218 THE PRACTICAL ELECTROPLATER. 

burner inserted in the other end, from which a flame about 
2 inches long is passed quickly backward and forward over 
the mold. This is done, in order to overcome the film of 
wax that is forced over the rules and cups of the letters in 
the operation of cutting down the displaced wax on the 
mold. The flame shrinks back the film and rounds the 
openings to the rules and types, which allows the brush to 
enter the cavities and properly blacklead the face and sides 
of the mold. 

Building up the Molds. 

This consists in raising the blank spaces in the mold 
with wax a sufficient height to produce a corresponding 
depression in the plate. This is done, in order to prevent 
the blank spaces from blacking the paper in printing, and 
is performed as follows : 

The operator, having selected a properly heated build- 
ing iron, several of which are laid on a gas stove in front 
of him, holds a thin strip of wax in contact with the 
heated iron directly over and about a quarter of an inch 
from the blank spaces, the melted wax being allowed to 
run down in the meantime from the end of the iron and 
over such blank spaces as it is desired to raise. 

The wax should be perfectly dry, as any moisture 
would cause it to sputter when brought in contact with the 
heated iron, thereby endangering the mold. 

In order to do this successfully, the operator should 
have a steady hand, that he may guide the melted wax 
smoothly and evenly over the blank spaces. An over- 
heated tool or a slip of the hand is apt to cause the melted 



CONNECTING THE MOLD. 219 

wax to run into the letters or over the face of the cut, 
which causes extra labor in repairing the plate, and some- 
times the damage is so serious as to necessitate the remold- 
ing of the work. A safe method is first to try the heat of 
the building iron by running a little wax from the tool on 
the case outside of the mold. 

Connecting the Mold. 

The building up having been properly performed, the 
operator proceeds to connect the face of the mold with one 
or more copper strips, each of which should be half an inch 
wide and about 6 inches long. These connections are 
carefully and firmly imbedded in the wax by laying the 
heated end of the cutting knife or building iron on the 
copper strips until they sink below the surface of the wax, 
after which some additional wax is run over the connec- 
tion with the building iron, in order to give them additional 
hold. 

It is essential that the wax be scraped from the surface 
of the imbedded copper strips, and that the exposed part of 
the wax around the connections be polished with plumbago. 
This is done, in order to insure a proper connection between 
the copper strips and the plumbago film on the face of the 
mold. 

After the connection strips are imbedded in the wax, 
the operator, with a soft brush, applies sufficient plumbago 
to barely cover the face of the mold. Do not fill the open- 
ings to the rules or the cups of the letters, as the plumbago 
is liable to pack in the cavities, thus preventing the brush 



220 THE PRACTICAL ELECTROPLATER. 

from entering and properly polishing the sides and face of 
the mold. 

Blackleading the Mold. 

Wax being a non-conductor, it is important that the 
mold should be well blackleaded and have a continuous 
and unbroken polished surface, otherwise the deposit of 
copper in the vat will be defective. In order to insure a 
perfect polish on the face and sides of the mold, it is neces- 
sary that the brush of the blackleading machine should be 
set perfectly level. 

A convenient method is to lay a flat case, free from 
wax, on the traveling bed of the machine, and then set the 
brush to the case. Then place the mold on the traveling 
bed of the blackleading machine and allow it to pass back- 
ward and forward under a laterally vibrating brush for 
about ten minutes, or until it is perfectly polished ; the 
copper strips or connections should be turned under in the 
meantime and allowed to fall freely between the openings 
in the traveling bed of the machine, in order that they may 
not become detached in the operation of blackleading. 

The molder will add to the success of this operation by 
rubbing the plumbago well into the sides of the rules and 
types with a moderately stiff brush before taking the im- 
pression of the form in the wax. 

Stopping Out the Mold. 

In order to prevent the copper from depositing on 
such surfaces beyond the mold as have become coated 



BLOWING OUT THE MOLD. 221 

I 

with plumbago, the operator scrapes the blacklead film 
from around the outside of the mold with a three cor- 
nered tool. This is done to destroy the conductivity of 
that portion of the mold where the deposit of copper is 
not wanted. By this means the metal case is entirely ex- 
cluded from the circuit, the slow and annoying method of 
painting the back of the case with wax avoided, and a great 
deal of electrical energy and copper is thereby saved. 

Blowing Out the Mold. 

After the mold is polished considerable blacklead will 
be found in the cavities, especially in the openings to the 




Scraper. 

fine rules and dots of the letters, which should be entirely 
removed before the mold is metallized. Great care must 
be used in this operation, as any neglect may cause defects 
in the shell, it being indispensable that the superfluous 
blacklead should be thoroughly washed out of the mold 
before it is placed in the vat. 

The superfluous blacklead is sometimes blown out of 
the mold with a bellows, but this is best performed by a force 
pump with a rubber hose, to which a sprinkler or rose 
nozzle is attached. 

This is performed by laying the case face up on a shelf 



222 THE PRACTICAL ELECTROPLATER. 

I 

in a trough, with only sufficient water to cover the face of the 
mold. The water is then turned on from the pump, after 
which the operator passes the sprinkler backward and for- 
ward over, and about 2 inches from, the face of the mold, 
for a few minutes, or until all the loose blacklead is forced 
out of the cavities. 

This will be found a reliable and economical method, as 
the water in use is less than 10 gallons and may be used 
continuously for the day's work. 

Metallizing the Mold. 

The credit of first making known the use of plumbago, 
whereby non-conducting surfaces, such as wax, &c, are 





Builder's Irons. 

made conductive, is due to Robert Murray, of England. 
This suggestion proved of inestimable value to those who 
desired to follow the electrotyping art commercially. 
Without the aid of this valuable substance it is doubtful 
whether the art would have gone beyond the bounds of 



METALLIZING THE MOLD. 223 

experiment ; but still plumbago is but an indifferent con- 
ductor, being less than 1 per cent, as compared with copper. 
When a wax mold, coated with plumbago and properly- 
connected, is placed in a sulphate of copper solution, the 
deposit is slow and tedious ; on the other hand, when a 
solid body of copper is placed in the same solution the en- 
tire surface is immediately covered with a coating of me- 
tallic copper. In following this principle several attempts 



Figure Gauge. 

have been made to supplant plumbago by means of bronze, 
copper and other metallic powders, all of which have been 
unsuccessful, either from a lack of proper adhesion to the 
wax mold or from the solvent action on the powders by 
the solution in the vat. 

While all efforts to supplant plumbago by means of 
metallic powders have been unsuccessful, it remained for 
Silas Knight, of New York, to discover a means whereby 
an instantaneous coating of metallic copper is thrown 



224 THE PRACTICAL ELECTROPLATER. 

down on the plumbago film before the mold is placed 
in the vat. 

Murray's suggestion made it possible to coat non-con- 
ducting material with a conducting surface, while Knight's 
discovery, when used in connection with the plumbago film, 
materially reduces the time of the deposit, as the mold is 
thereby provided with a surface of an eminent conducting 
quality, by which means the uniformity of the deposit over 
the entire surface is insured. Without such preparation the 
deposit of copper would take place slowly, and gradually 
spread itself over the surface of the mold. Those portions 




Line Holders. 

nearest the connections would therefore receive the heaviest 
deposit, and those farthest therefrom the thinnest. 

When used in connection with the plumbago film, the 
metallizing process effects in a few seconds a uniform coat- 
ing of metallic copper over the face of the mold, thereby in- 
suring a uniform and rapid deposit on the mold in the vat. 

Striking Solution. 

This solution is used in metallizing the molds, and is 
composed of 2 pounds of sulphate of copper crystals to each 
gallon of water. Do not add sulphuric acid to this solu- 
tion, as it will cause the iron filings to heat, and burn the 
face of the mold. 



STRIKING SOLUTION. 225 

The operation of metallizing the mold is performed in 
the following manner : After the superfluous blacklead is 
blown out of the cavities, the mold is laid face up on a level 
shelf in a sink or trough. The operator then ladles out of 
a conveniently placed vessel sufficient striking solution to 
cover the face of the mold, and immediately sprinkles 
thereon, from a perforated box or sieve, fine cast iron filings 
free from dirt, oil or grease. 

A fine, long haired flat brush is used to intermix the 
filings with the solution, by first tapping the mixture lightly 
with the brush, and then quickly spreading it backward and 
forward over the mold. The iron having more affinity for 
the acid than for the copper, the latter is set free and 
thrown down on the mold in a bright reguline state. 

Immediately after the above operation thoroughly 
rinse the mold with a strong head of water, as the mixture, 
if allowed to remain, will heat and destroy the face of the 
mold. The best way to perform this is to force the water 
through a rubber hose directly into the cavities and over 
the face of the mold, until all the iron filings are washed 
off. Should any spots remain uncovered, repeat the opera- 
tion until the entire surface is covered with a film of copper. 
The operator should be careful to rinse the brush w r ith 
water immediately after every operation, as the metallic 
copper in the solution will adhere to the tip end of the 
brush, and if allowed to remain will scratch the face of the 
mold. 

The brush should be avoided on all cut work, and the 
following simple and safe method adopted : Flood the face 
of the mold with the striking solution, and after sprinkling 



226 



THE PRACTICAL ELECTROPLATER. 



the iron filings evenly thereon reduce the supply of water 
in the rose nozzle to a fine spray, which should be allowed 
to fall gently on the mixture until the metallic copper is set 
free and thrown down on the mold. This operation should 
be repeated until the entire surface of the mold is thor- 
oughly covered with a coating of copper. Before the molds 




Adjustable Lead and Slug Mold. 

are placed in the vat the solution must be made up ready 
to receive the work. 

Sulphate of Copper Crystals (Bluestone) 

While it is not absolutely necessary for the operator to 
have a thorough knowledge of chemistry, it is essential in 
order to produce a smooth and tough deposit of copper 
that he should understand the composition of his solution 
and the laws governing the same. 

Sulphate of copper crystals consists of one equivalent 
of sulphuric acid, 40 ; one of protoxide of copper, 39.75, 



SULPHATE OF COPPER CRYSTALS. 227 

and five of water, 45=124.75, or, in other words, the crystals 
contain about one-third acid, one-third copper and one- 
third water, and are obtained by heating sulphuric acid and 
copper together, dissolving the soluble product in hot 
water and evaporating the solution until crystallization 
takes place in cooling. Sulphate of copper crystals has a 
rich blue color and a strong metallic, styptic taste ; it red- 
dens vegetable blues and crystallizes in transparent prisms, 
which effloresce slightly in the air, and is soluble in four parts 
of cold and two of boiling water, but insoluble in alcohol. 
When heated, it first melts in its water of crystallization 
and then dries and becomes white. 

If the heat is increased to a high temperature it finally 
loses its acid, protoxide of copper being left. Potassa, 
soda and ammonia throw down from it a bluish white pre- 
cipitate of hydrated protoxide of copper, which is immedi- 
ately dissolved by an excess of the last mentioned alkali, 
forming a rich deep blue solution. It is decomposed by 
the alkaline carbonates, and by borax, acetate and subace- 
tate of lead, acetate of iron, nitrate of silver, corrosive 
chloride of mercury, tartrate of potassa and chloride of 
calcium, and is precipitated by all astringent vegetable in- 
fusions. If it becomes green on the surface by the action 
of the air, it contains oxide of iron. This oxide may be 
detected by ammonia, which will throw it down along with 
the oxide of copper without taking it up when ammonia is 
added in excess. When zinc is present it will be taken up 
by a solution of potassa added in excess, from which it may 
be thrown down in white flocks by a solution of bicarbon- 
ated alkali. 



228 THE PRACTICAL ELECTROPLATER. 

The operator cannot be too careful in the choice of 
sulphate of copper, of which three distinct varieties are 
found in the market. The best is produced from the treat- 
ment of copper or its oxide with concentrated sulphuric 
acid, and is known in the trade as C. P., or chemically 
pure. 

This sulphate comes in the shape of crystals, semi- 
transparent and of a fine blue color ; its solution is also a 
pure blue, and is principally selected for dyeing fine woolen 
fabrics, where the presence of a trace of iron would inju- 
riously affect the color. It should also be used by electro- 
typers, owing to its purity. 

Sulphate of Copper Solution. 

A very important part of the electrotyping process is 
preparing the solution, and in such a way that the deposit 
will rapidly cover the surface of the mold with a flexible 
copper shell. The directions in technical works are well 
enough for metallic surfaces, but do not answer the re- 
quirements of blackleaded wax molds. 

The best method is to fill the vat two-thirds full of 
water, free from lime. If lime is present in the water, it 
will reduce the conductivity of the solution by absorbing 
the acid, and the result will be a brittle deposit. 

Filling the vat only two thirds full of water will allow 
for the addition of the required amount of sulphate of cop- 
per crystals and sulphuric acid, and also for the displace- 
ment caused by hanging the anodes and cathodes in the vat. 

In order to saturate the water to the proper density, 
suspend in the upper portion of the vat (in cheesecloth 



SULPHATE OF COPPER SOLUTION. 229 

bags) 1% pounds of copper crystals to each gallon of 
water. 

As soon as the water is impregnated with the salts, it 
becomes denser and of greater specific gravity and gradu- 
ally sinks to the bottom. Do not throw the salts in the 
bottom of the vat, as the layer of water in contact with 




Safety Hook. 

them soon becomes saturated, and being denser than the 
liquid above, does not readily mix with, but, on the con- 
trary, forms a saturated solution surrounding the crystals. 
When the crystals have dissolved for some time, stir the so- 
lution with a wooden paddle and test with an acid hydrom- 
eter. When the solution shows a density of 14 , the bags 



230 THE PRACTICAL ELECTROPLATER. 

containing the salts should be removed from the vat and a 
gill of sulphuric acid added to each gallon of water, in or- 
der to raise the solution to i6°. It should then be allowed 
to cool off for ten or twelve hours, stirring frequently in the 
meantime to incorporate the acid well into the solution. 
When the solution has thoroughly cooled off the copper 
anodes are then hung by the s hooks on the anode rod, 
the operator being careful to observe that the points of 
contact between the hooks, the anode and the anode rod 
are perfectly clean. 

If electrically deposited or chemically pure anodes are 
used, the solution will keep in a uniform condition, except 
as regards the loss of water by evaporation. But if impure 
anodes are used, the bath gradually becomes charged with 
soluble metallic impurities, which in time will impregnate 
the solution, the consequence of which will be a brittle de- 
posit or shell. This is a source of annoyance to electro- 
typers, as the backing metal (even though containing a 
large proportion of tin) will not adhere to a brittle shell. 

It is also of much importance that the anodes should 
be free from arsenic, iron or zinc, as it is well known that 
one-fifth per cent, of iron depreciates the conductivity of 
copper 25 per cent., while a mere trace of arsenic reduces 
its conductivity over 50 per cent. 

A deposit from a neutral solution of copper is rough, 
irregular and brittle, but, if tin is present, the deposit is ex- 
cellent and tough, even though it shows no trace of tin. 
The resistance of the solution is also much reduced by the 
presence of tin in the anodes. 

When the bath becomes surcharged with iron, zinc, &c, 



SULPHATE OF COPPER SOLUTION. 231 

a portion of the solution should be removed from the bot- 
tom of the vat, from time to time, by a siphon, and re- 
placed by a like amount of water and a few gills of sul- 
phuric acid. The water is added to reduce the density of 
the solution, while the acid dissolves the iron, zinc, &c. 

Should crystals form on the anode or around the sides of 
the vat, add water free from lime to reduce the density and 



Connecting Clamp. 

to make up for evaporation. If the solution becomes too 
dense, which is owing to an excess of sulphate, a burnt or 
sandy deposit will be the result, and if not attended to at 
once by the addition of water the deposit will finally be- 
come brittle. 

If the solution becomes too sour, which is owing to an 
excess of acid, streaks will appear on the back, and the 



232 THE PRACTICAL ELECTROPLATER. 

shell in time will become brittle. This is remedied by 
siphoning about 10 per cent, of the solution from the bot- 
tom of the vat and adding the like amount of water. 

Another method is to add about an ounce of whiting 
to each gallon of the solution, to neutralize the excess of 
acid. 

It is important that close attention be paid to keeping 
the solution in a uniform condition, as an excess of acid or 
protoxide of copper, or the lack of a proper proportion of 
either, or the surcharging of the solution with metallic im- 
purities, will produce imperfect results and cause expensive 
delays. 

In order to keep the solution in proper working order, 
mark the height of the solution in the vat, and in the 
morning, before taking out the work, add water to make 
up for evaporation. 

About once every week place 25 pounds of sulphate of 
copper in a perforated box or cheesecloth bag, and hang it 
in the vat, to enrich the solution. 

Remember that every pound of copper crystals added 
to the solution contains about one-third water, one-third 
acid and one-third copper. 

Depositing the Shells. 

Having thoroughly washed out the iron filings, the 
molds should be placed back to back, and hung by the 
safety hooks on the rubbers of the cathode rod, the case 
being allowed to swing freely in the solution, and about an 
inch from the anode or coppers. Be careful that the solu- 



DEPOSITING THE SHELLS. 233 

tion fully covers that part of the copper connection strips 
which are attached to the mold. The solution should also 



Mold Connected. 



be prevented from rising to the height of the hooks by 
attaching an overflow pipe to the vat on a line with the 
solution ; otherwise the copper will form a deposit on the 



234 



THE PRACTICAL ELECTROPLATER. 



cathode hooks, while the hooks on the anode will be eaten 
away. 

The first mold placed in the solution should face the 
copper at the extreme end of the vat and be immediately 
connected with the cathode rod, by placing the connection 
strip of the mold directly under the thumbscrew of the 
improved clamp, which is attached to the cathode rod. 
The thumbscrew should be turned tightly down on the 




Depositing Tank. 



copper connection strip, and allowed to remain until the 
desired thickness of shell is obtained. 

Having properly connected the first mold, the re- 
mainder are similarly treated until the last mold is placed 
in the solution opposite the anode nearest the dynamo. 

In order to secure a perfect connection and a proper 
flow of the electric current, it is absolutely necessary that 
the contact point of the positive and negative poles, 
the anode and cathode rods, all anode hooks, and the con- 



STRIPPING THE COPPER FROM OLD PLATES. 235 

nection strips of the molds should be perfectly clean. 
These instructions are important and should be closely 
observed, as a proper contact is necessary to complete the 
circuit. 

If the molds are not properly blackleaded, the copper 
deposit will show small black spots, especially on the sides 
of the letters, which, if the shell is removed, turn out to be 
holes. In such a case the mold should be taken from the 
vat and rinsed with clean water, after which a thick solution 
of plumbago and water, or, better still, plumbago and 
alcohol, is rubbed into the defective parts by means of a 
moderately stiff brush. The molds are then hung on the 
anode rod and allowed to remain in the solution for about 
a minute in order to chemically clean the back of the 
shells, after which they are transferred to the cathode rod. 
By this means the defective parts will be properly covered 
with copper, and a proper adhesion insured between the old 
and new deposit, which otherwise would blister or separate 
in the process of backing. 

Stripping the Copper from Old Plates. 

Old electrotype plates may be utilized as temporary 
anodes by first depositing a thin film of copper on the 
molds from the regular anode, after which the plates, if 
large, are hung in the solution by suitable hooks, and al- 
lowed to remain until all the copper is stripped from the 
face of the plate. 

Should the plates be small, a convenient method of 
joining them is to lay several face down in the heated cast- 
ing pan and then pour hot metal (or buttons) on the back 



236 THE PRACTICAL ELECTROPLATER. 

of the plates. By this means the old plates are securely 
joined and maybe prepared when the operator is not other- 
wise employed. Old shells, connection hooks and parts of 
anodes or other copper, may also be utilized by being 
placed in perforated boxes hung in the solution opposite 
the case or cathode. These boxes (usually 2 inches thick 
and the length and width of the cases) may be made from 
lead or from electrotype metal in use in the foundry and 
the parts joined by the same material. Never use tin or 
solder to connect its joint, as the tin will be acted on by 
the solution. 

The Dynamo. 

The magneto-electric machine has been displaced for 
practical use by the dynamo-electric machine, or dynamo, 
the distinction being that in the former a permanent mag- 
net is employed, while in the latter its place is taken by an 
electro-magnet. 

Dynamos have a high degree of efficiency, trans- 
forming, in some cases, nearly 90 per cent, of the mechani- 
cal energy used in revolving the armature into the energy 
of the electric current. They also furnish the electric cur- 
rent much more economically, as well as more regularly, 
than a voltaic battery, since the zinc, the fuel of the latter, 
is expensive and poor as compared with coal which creates 
the power that drives the dynamo. 

In some forms of the machine the field magnets are 
excited by independent currents produced by separate ma- 
chines ; in other forms, called series dynamos, the current 
generated in the armature charges the field magnets, and 



THE DYNAMO. 237 

is also used for the outside work. In still other forms, 
called shunt dynamos, a portion only of the current gener- 
ated in the armature is used to charge the field magnets, 
the remainder being taken off for the practical outside 
work. 

The dynamo machines in use are of many forms, but 
all consist essentially of one or more large electro-magnets 
called the field magnets, between the poles of which an 
armature, consisting of a soft iron core, wound with coils 
of insulated copper wire, is made to revolve very rapidly. 
In most of these machines the principle of reduplication is 
involved — that is, commencing with a very small amount 
of residual magnetism in the field magnets, the inductive 
action between them and the revolving armature results in 
the production of a feeble current in the coils. This cur- 
rent is made to pass through the wire of the stationary 
magnets, strengthening them so that they exert a stronger 
inductive influence in the armature, thus producing a strong 
current in the coils, which again charges more strongly the 
field magnets, and so on until the machine is in full action. 

The current generated is taken from the commutator 
of the dynamo by means of metallic brushes, and is almost 
instantly transmitted along the positive pole to the anode 
rod, down the S hooks to the anode, through the solution 
to the mold, and back again by way of the connection 
strips to the cathode rod, whence it re-enters the machinery 
by way of the negative pole. 

As the current passes through the vat the solution be- 
comes decomposed, its copper being gradually deposited 
on the cathode or mold, while the liberated sulphuric acid 



238 THE PRACTICAL ELECTROPLATER. 

dissolves an equivalent proportion of copper from the 
anode, forming sulphate of copper, by which the strength 
of the solution is kept uniform, or, in other words, the 
copper is deposited on the mold at the same rate that it is 
dissolved from the anode — that is, so far as the impurities 
of the anode will allow. 

Removing the Shell from the Mold. 

When the desired thickness of shell is obtained, the 
mold is taken from the vat and placed in the sink in a 
slanting position, and the connections liberated by means 
of a sharp pointed tool or knife, after which the operator 
pours hot water over the back of the shell while he gently 
lifts one corner. The heat of the water melts the surface 
of the wax immediately in contact with the under part of 
the shell. This allows the workman to relieve the shell 
from the mold while the water is being poured over it. 
The shell should be removed carefully and with a slight 
tension, in order to keep it straight and free from kinks. 

A great deal of extra and expensive labor may be 
avoided in finishing the plates by carefully handling and 
backing the shells. 

EVAPO RATING THE WATER FROM THE WAX. 

While the shells are being removed from the wax 
molds considerable water is retained in the blisters that 
gather on the face of the composition, which should be en- 
tirely removed before the wax is again used. If allowed to 
remain the water will injure the working qualities of the 
composition, besides showing itself by small pin holes and 



CLEANING THE SHELLS. 239 

blisters appearing on the face of the mold after the im- 
pression is taken. 

Some molders evaporate the water by placing the wax 
in an iron pot over a gas flame or over the heated metal. 
This is an unsafe method, as dry heat destroys the glutinous 
nature of the composition, and should the wax overflow 
into the flame or metal pot the results would be threaten- 
ing, if not seriously dangerous. 

The best method is to use two steam wax pots, one of 
which should be directly under the overflow pipe, into 
which the melted wax from the table is allowed to flow, 
and remain until all the water is evaporated. 

After the moisture is entirely evaporated the wax may 
be transferred to the other pot. The remaining cases are 
now placed on the steam table, and the melted wax allowed 
to flow into the first pot. The operator in the mean- 
time proceeds to run the wax into the cases from the second 
pot. 

Cleaning the Shells. 

A film of wax, which must be removed before the shell 
is tinned, adheres to the face of the shell when it is being 
relieved from the mold. If the wax is allowed to remain 
it will be burnt to carbon and form in hard crusts under 
the shell in the process of backing, thus causing innumer- 
able sinks and extra labor in finishing the plates. This 
wax is removed by laying the shell face up on a flat board, 
placed in a slanting position over the lye pot, while the 
operator pours hot lye over the shell and at the same time 
rubs it lightly with a soft brush until the wax is entirely 



240 THE PRACTICAL ELECTROPLATER. 

removed. The lye should be allowed to flow back into 
the pot, and the wax taken off from time to time and 
placed on the steam table to be remelted. 

After having removed the wax from the face of the 
shell the back is thoroughly rinsed in clean water, in order 
to remove any lye that may have gathered thereon. If the 
lye is allowed to remain on the back it will prevent the tin 
foil from uniting with the shell in the process of tinning. 

Having cleaned the shells, place them in a shallow 
lead lined box about 18 inches wide, 20 inches long and 
about 4 inches deep. This box is nearly filled with water, 




Lye Brush. 

to which is added 2 per cent, of sulphuric acid. The shells 
are allowed to remain in this solution until ready for the 
tinning process. This is a necessary precaution, as the 
solution prevents the back of the shells from becoming 
oxidized or tarnished. Renew the solution about once a 
week 

Tinning Solution. 

Electrotype metal will not of itself amalgamate with 
copper. It is therefore necessary to unite the metal with 
the shell by means of tin foil, and as the tin foil will not 
adhere properly to the shell unless the back is made chem- 
ically clean, a tinning solution becomes necessary. 



TINNING THE SHELLS. 241 

This solution is prepared in a wide mouthed glazed 
earthen jar or bottle as follows : 

Pour about a pint of muriatic acid into a quart jar and 
add half a pound of zinc straps. A strong boiling action 
takes place immediately, the fumes of which are very un- 
healthful to persons having weak lungs. It is therefore 
necessary that this solution should be made in the open 
air, when the wind is blowing in the opposite direction. 
When the boiling action has ceased and no more gas is 
given off, pour the clear solution (now chloride of zinc) 
into a wide mouthed jar, and add about one-third water to 
reduce the acid, and an ounce of sal-ammoniac to neutral- 
ize the salts of zinc. When the sal-ammoniac has dissolved 
the solution is ready for use. 

Before the tinning solution is applied the shells should 
be examined, and if any holes appear dry blacklead should 
be rubbed in on the face by means of a soft brush, or the 
backing pan may be rubbed with a mixture of half oil and 
blacklead before the shells are tinned. Either of these 
methods will prevent the backing metal from coming 
through the holes in the shells. 

Tinning the Shells. 

The next operation is tinning the shells, and is per- 
formed by laying sufficient shells face down to cover a level 
board cut to the inside measure of the backing pan. 

After the shells are laid on the board, the workman, 
with a moderately stiff brush, rubs the tinning solution well 
into the cavities and over the back of the shells, after 



242 



THE PRACTICAL ELECTROPLATER. 



which they are held on edge over the jar to drain off any 
excess of the solution. 

Sufficient tin foil to fully cover the back of the shells 
is then laid thereon, after which they are immediately 
placed in the previously heated backing pan. It is abso- 




Mold Brush. 



lutely necessary that the pan should have a smooth and 
level surface, and should always be kept in that condition, 
as any irregularities on the surface of the pan will assert 
themselves on the face of the shell in the backing process. 
The pan containing the tinned shells is then placed on 
the molten metal in the casting pot. The temperature of 



TINNING THE SHELLS. 243 

the metal should be kept uniform, and heated sufficiently to 
color a dry white paper dark brown. 

Do not overheat the metal, as the tin is liable to burn 
and form as dross on the surface of the pot. If the metal 
becomes too hot it will distort the shells, causing extra 
labor in finishing the plates. 

When the pan has attained the same heat as the molten 
metal, the tin foil melts and amalgamates with the copper 
shells. 

Particular attention should be paid to pouring the molten 
metal on the shells immediately after the tin fuses, as the 
heat evaporates the acid of the tinning solution, leaving 
the salts of zinc in a soft state on the shells. This salt, 
when soft, will float to the top of the cast, if the operator 
pours the molten metal on the shell, as soon as the tin 
fuses. But should the shells be allowed to remain too long 
in the heated pan the salt (having lost its acid) will form 
hard, white crusts in the bowls of the letters, and tena- 
ciously remain there while the metal is being poured on the 
shells. This crust prevents the molten metal from enter- 
ing the cavities of the shells, in consequence of which the 
metal bridges over the openings and causes what are termed 
in the trade " soft faced " letters. These soft faced letters 
are a source of much annoyance not only to the electro- 
typer, but to the pressman, as sometimes no outward indi- 
cation of their presence is noticeable until after the plates 
are made ready on the press. 

Immediately after each cast the operator should wipe 
the surface of the backing pan with a wet cloth or swab. 
This is done that the wax may not form in hard crusts 



244 THE PRACTICAL ELECTROPLATER. 

when cold, and also to prevent the acid from corroding the 
face of the pan. 

Electrotype Backing Metal. 

In order that the backing metal may properly adhere 
to the tinned shells, it should be made of 

One hundred pounds of lead, 
Three pounds of tin, and 
Four pounds of antimony. 

Do not use either type or stereotype metal in backing 
electrotype shells, unless the same is reduced by lead to the 
proper proportions of electrotype metal, as the antimony 
(being in excess and having a greater affinity for the tin 
than tin has for the copper) absorbs the tin from the back 
of the shell, causing what is termed "peeling." 

Stereotype metal is composed of 

One hundred pounds of lead, 
Eight pounds of tin, and 
Fifteen pounds of antimony. 

Type metal contains 

One hundred pounds of lead, 
Sixteen pounds of tin, and 
Thirty pounds of antimony. 

Backing the Shells. 

After the tin foil has fused on the shells, the backing 
pan in which the latter are laid is then removed from the 
metal pot and placed on a perfectly level stand, in order to 
insure a uniform thickness of metal in the cast, after which 
the electrotyper immediately pours the molten metal 



CLEANING THE PLATE. 245 

through a heated perforated ladle on the shells. By this 
means the weight of the body of metal is checked and falls 
in fine streams, gradually distributing itself over the shells, 
after which the cast is allowed to cool off. The cooling of 
the cast is rapidly done by means of a small blower placed 
in a convenient position, and connected to a wide mouthed 




Sieve Brush. 

funnel under the backing pan. Or the blower may be re- 
versed to exhaust the foul air from the room while cooling 
the pan. 

Cleaning the Plate. 

After the cast is taken from the backing pan it is 
turned face up on a suitable stand or table, and all remain- 
ing wax, acid or plumbago is removed by scouring the face 



246 THE PRACTICAL ELECTROPLATER. 

of the plate with benzine, pulverized pumice stone, and a 
stiff brush. 

Or the wax may be removed by pouring kerosene oil 
on the face of the cast ; the oil dissolves the wax, and is in 
turn removed by brushing fine sawdust over the face. The 
cast is then dried and all remaining pumice stone or saw- 
dust brushed, off, after which it is ready to be sawed up. 

This is done by means of a circular saw, by sawing the 
superfluous metal from around and close up to the guards 
on the plate. 

Straightening the Plates. 

After the plates are sawed from the cast they are care- 
fully inspected, and, if satisfactory, the operator beats down 
with a suitable hammer those portions of the guards that 
may have become higher than the printing surface of the 
plate. This is done that the face may be examined under a 
straightedge, and if found uneven the plates are partly or 
rough straightened, in order that they may lie level on the 
bed of the planing machine. 

The first cut is now taken from the back of the plates, 
after which the latter are restraightened. This is a delicate 
operation, and careful judgment is necessary, as the opera- 
tor must not only understand the condition and composi- 
tion of the metal, but he must also realize the value of 
every stroke of his hammer, in order to avoid battering or 
damaging the face of the plates. 

In order to locate the sinks or low spots, the surface of 
the plate is rubbed lightly with a hard rubber (such as is 
used for ink erasers) to which a small wooden block is 



SHAVING THE PLATES. 247 

glued. By this means low spots are left unpolished, and 
may be indicated on the back opposite the sinks by means 
of a calipers or markers used expressly for this purpose, 
after which the plate is turned over and tapped lightly on 
the back and cleaned with a stiff brush in order to free it 
from any particles of metal or grit, which, if allowed to re- 
main, would be liable to be imbedded in the surface of the 
plate in the operation of beating up the sinks or low spots. 

The plate is now laid face down on the steel slab, or on 
a thin cardboard laid in the steel slab, and the places marked 
on the back by the markers are carefully beaten up to a 




Mold Brush. 

true surface with the face by means of the ball end of a 
hammer or punch, after which the sides and ends are 
brought up and the plate made level with a straightedge. 

Shaving the Plates. 

After the plates are finally straightened they should be 
shaved to a standard gauge — say, small pica. 

It is important that the knife in the shaving machine 
should be set perfectly true, and all the plates shaved to 
the same gauge (except titles, half titles and copyright 
pages, which should be shaved a thick paper lower); if this 
rule is followed every press in the office may be set to the 



248 THE PRACTICAL ELECTROPLATER. 

same gauge, otherwise the cost of presswork will be greatly- 
increased by unnecessary overlaying and underlaying of 
plates. 

Beveling the Plates. 

The plates having been shaved to the desired thickness, 
a proof is taken on a hand press, after which the guards are 
then cut off by means of a circular saw, and the plates 
beveled on the sides and foot, and the head trimmed to 
within a thin lead of the folio or running title. 

The beveling machine cutters should be sharpened to a 
set gauge in order to insure a uniform bevel on the plates. 

Routing the Plates. 

After the plates are beveled the blank spaces are cut 
down sufficiently low to prevent the ink from blacking the 
paper in printing. This is best done by means of a rout- 
ing machine. 

Finishing the Plates. 

After the plates are trimmed and beveled they are care- 
fully examined, and all the necessary matter that was left 
in routing or that will show in printing must be cut down 
below the shoulder of the type. 

All the battered or imperfect letters should be picked 
up and reshaped, if possible, or new type inserted in their 
places. 

The blank spaces should be carefully looked over to see 
if any type or parts of cuts have been built off with wax 
in the operation of raising the blank spaces in the mold. 



I 



FINISHING THE PLATES. 249 

Should it become necessary to make corrections in 
plates — such as the changing of a letter or even a few- 
words — type may be used. But should the corrections 
necessitate the use of considerable type, or the alterations 
be of such a character that the matter must be transposed 
or overrun, the defective part should be reset and the pieces 
cast. The folio of the page in which the corrections occur 
should be set over each piece, and a proof of the pieces, 
together with the marked proof of the plate, should be 




Finisher's Brush. 

sent to the foundry as a guide to the finisher while making 
the corrections. 

After the pieces are cast they are straightened in the 
usual manner and shaved to the desired thickness, and are 
then trimmed to suit the page. 

The defective matter is now cut off and the new pieces 
properly adjusted, after which they are securely joined on 
the back by means of a solder composed of equal parts of 
lead and tin. 

The tinning solution used in tinning the copper shells 
is used as a flux for the solder, and is usually kept in a small 
bottle and applied to the joints of the plate before solder- 
ing by means of a small brush or stick. 

It is important that the soldering iron should be well 
heated, in order that the solder may flow freely and amal- 



250 THE PRACTICAL ELECTROPLATER. 

gamate properly with the electrotype metal ; otherwise the 
joints are liable to separate on the press and cause con- 
siderable damage. 

Plates Mounted on Wood. 

Plates not intended for patent blocks are generally styled 
jobwork, and are usually shaved to small pica gauge, after 
which they are trimmed on all sides and mounted type high 
on either wood or metal. The wood on which the plates 
are mounted may be either oak, cherry or mahogany, and 
should be free from checks, knots and soft spots, and may 
be planed to the desired thickness ; but when accuracy is 
desired the wood should be shaved on a machine with an 
adjustable head, to which is attached a parallel knife. 
With this machine metal or wood may be shaved accurately 
and to the desired thickness. 

Some operators fasten the plate to the wooden block by 
first punching a hole in the plate with a brad awl, through 
which they drive a five-eighths No. 17 or 18 round iron nail 
directly through the plate into the wood. 

When the space will admit, the safest plan is to use 
half inch No. 3 or 4 flat head wood screws, especially on 
large plates. The holes for the screws should be counter- 
sunk, that the screws may set well into the plate, while the 
nails should be driven home by a nail set or punch, in order 
to prevent the heads from blacking the paper in printing. 

Plates Mounted on Metal. 

All electrotypes that are intended for newspapers, or 
from which duplicates are to be made, should be mounted 



NICKEL FACING ELECTROTYPES. 251 

on metal bases. This may be done by either of the follow- 
ing methods : 

The plate maybe heated and joined to the base by the 
use of a fusible alloy composed of the following metals : 

Eight ounces bismuth, 
Four ounces lead, 
Four ounces tin, 

or they may be soldered with a heated soldering iron and 
a composition composed of equal parts of lead and tin ; or 
by laying the plate face down in a heated mold and 
pouring the molten metal thereon, after which the mounted 
plates may be trimmed square by a hand planer ; but this is 




Finisher's Calipers. 

best performed by means of a metal body trimmer used 
expressly for that purpose. 



Nickel Facing Electrotypes. 

In printing from electrotypes with colored inks, but 
more especially with inks which are prepared from a mer- 
curial pigment, such as vermilion, not only is the surface 
of the electrotype injuriously affected (by the mercury 
forming an amalgam with the copper), but the brilliant 
colors are also seriously impaired by the decomposition 
which occurs. 

To avoid this it is best to give electrotypes to be used 
for such purposes a coating of nickel, which effectually 



252 THE PRACTICAL ELECTROPLATER. 

protects the copper from injury, and seemingly brightens 
the color of the ink. 

It is absolutely necessary that the face of the electro- 
type should be chemically clean, in order that the nickel de- 
posit may properly adhere to the copper. 

A convenient method is to drill holes in the plates and 
suspend them by copper hooks in a boiling hot solution of 
potash for about ten minutes. The plates are then re- 
moved and scoured by means of pulverized pumice stone 
and a stiff brush, after which they are thoroughly rinsed in 
running water and next dipped for an instant in a solution 
containing a quarter of a pound of cyanide of potassium 
to each gallon of water. 

The plates are again rinsed in running water and imme- 
diately suspended in the nickel bath about 2 inches from the 
anode, where they are allowed to remain for about twenty 
minutes, or until the desired deposit is obtained ; after 
which they are dipped for a few minutes in boiling water 
and laid aside to dry spontaneously. 

Should the deposit appear burnt on the edges the re- 
sistance should be increased by separating the plates about 
3 inches from the anode. 

Nickel Solution. 

This solution should be made up of about three- 
quarters of a pound of double sulphate of nickel and am- 
monia to each gallon of warm water. 

The sulphate or salts should be inclosed in cheese- 
cloth bags and suspended in the upper portion of a vat 
filled about three-quarters full of water until entirely dis- 



STRIPPING NICKEL FROM ELECTROTYPES. 253 

solved, after which it should be well stirred to thoroughly 
mix the solution, when it is ready for use. 

The resistance of a nickel solution is reduced 25 per 
cent, by the addition of 10 per cent, of common salt, be- 
sides producing a whiter and more flexible deposit. 

As a rule only a limited quantity of nickel can be de- 
posited ; if this amount is exceeded the deposit will sepa- 
rate from the underlying metal or copper. 

A very thin coating is all that is necessary, as nickel is 
an exceedingly hard metal and will bear considerable fric- 
tion. Unlike steel, it will not tarnish or corrode : for 



Finisher's Type Saw. 

these reasons it has superseded steel and is now applied in 
facing the curved electrotype plates used in printing the 
Century Magazine. 

These plates (which had a twenty minutes' deposit of 
nickel) were examined after an edition of over 200,000 
copies had been printed from them on a web press with 
hard packing. The nickel facing was found to be not en- 
tirely worn off, and the underlying copper was intact. 

Stripping the Nickel from Electrotypes. 

When electrotype plates that have been nickeled re- 
quire to be replated it is absolutely necessary that the old 
plates be thoroughly cleaned and afterward hung for a few 



254 THE PRACTICAL ELECTROPLATER. 

seconds on the anode and then transferred to the cathode 
rod. By this means a chemically clean surface is obtained 
and a proper adhesion insured between the new and the old 
deposit. When it is desired to strip the copper from elec- 
trotype plates that have been nickeled a solution for strip- 
ping the nickel from the copper is first necessary. A 10 
gallon bath for this purpose should be composed as follows : 

Ninety-six fluid pounds of oil of vitriol. 
Twenty-four fluid pounds of nitric acid. 
Three gallons of water. 

Add the oil of vitriol to the water gradually ; not the 
water to the vitriol, which is dangerous. 

When the mixture has cooled down add the nitric acid 
and stir with a wooden paddle, and when the solution is 
cold it is ready for use. 

The plates to be stripped should be attached to stout 
copper wires and hung in the solution for about a minute, 
when the nickel will be entirely dissolved, after which they 
should be rinsed in cold water. 

This operation should be performed in the open air, or 
the bath should have a bonnet, to which is attached a pipe 
to carry off the acid fumes. 

Electrical Units. 

There has been much diversity of opinion among 
electricians as to the best system of electrical measurement 
to be founded on the various theories of Ohm, Weber, 
Thomson, Ampere and others ; but as a general rule the 
volt is accepted as the unit of electromotive force, the ohm 



ELECTRICAL RESISTANCE. 255 

as the unit of resistance, and the ampere as the unit of 
quantity or current strength, which determines the amount 
of electric work done in a given time. In estimating the 
electric power of a dynamo electric machine its electro- 
motive force is given in volts, its resistance in ohms, and 
its quantity of strength is given in amperes ; thus, a ma- 
chine for depositing copper (which does not require a 
current of high tension ) may have an electromotive force 
of 1 or 2 volts, with a resistance of 0.5 ohm and a current 
of 800 or 900 amperes or more. 



Electromotive Force. 

Electromotive force is that quality of a voltaic battery 
or other source of electricity in virtue of which it tends to 
do work by the transfer of electricity from one point to 
another, and this force is gauged by measuring the work 
done during the transfer of a given quantity of electricity 
between these two points. The electromotive force is, in 
fact, the strength of power of the current to overcome 
resistance. The unit of electromotive force is termed a 
volt. 

Electrical Resistance. 

By this is understood that quality of a conductor in 
which it prevents the performance of more than a certain 
amount of work in a given time by a given electromotive 
force. The resistance of a conductor is therefore in- 
versely proportional to the work done in it when a given 



256 THE PRACTICAL ELECTROPLATER. 

electromotive force is maintained between the two ends. 
The unit of resistance is termed an ohm. 

Electrical Current. 

By this term is meant the cause of the peculiar prop- 
erties possessed by a conductor used to join the opposite 
poles of a voltaic battery ; namely, those of exerting a force 
on a magnet in its neighborhood ; of decomposing certain 
compound bodies called electrolytes, when any part of the 
conductor is formed of such compound bodies ; or of pro- 
ducing currents in neighboring conductors as they ap- 
proach or recede from them. 

Quantity. 

The force with which one electrified body acts upon 
another at a constant distance varies under different circum- 
stances. When the force between the two bodies, at this 
constant distance and separated by air, is observed to in- 
crease, it is said to be due to an increase in the quantity of 
electricity, and the quantity at any spot is denned as pro- 
portional to the force with which it acts through air on 
some other constant quantity at a distance. If two bodies 
charged with a given quantity of electricity are incor- 
porated, the single body thus composed will be charged 
with the sum of the two quantities. 

All the most striking properties of electricity — such as 
the decomposition of water and salts, the combustion of 
metals, the deflection of the galvanometer, the attraction of 
the electro-magnet and the physiological effects of the cur- 



OHM'S LAW. 257 

rent — are really dependent, as regards their magnitude and 
energy, solely on the quantity of electricity passing. Their 
greater energy, when the tension is increased, is an indirect 
effect due, not to tension, but to the increased quantity 
which passes in a given time by reason of the increased 
tension. The unit of current strength is termed an ampere. 

Ohm's Law. 

Under the most favorable conditions it is well known 
that from a voltaic battery a full equivalent of electrical 
power is never obtained in return for the chemical action 
which takes place within the battery cell, and this loss of 
power is due to internal resistance within the battery. This 
internal resistance is overcome when several cells are con- 
nected in alternate series, that is, the zinc of one cell with 
the copper of the next, and so on throughout the series. 

The world is indebted to Professor Ohm, of Nuremberg, 
for an exposition of the causes which influence the quantity 
of electricity obtained in a voltaic circuit. He investigated 
the subject mathematically, and his formulas have been 
verified by Wheatstone and others, and are regarded as the 
basis on which all other investigations relative to the force 
of current are founded. Ohm's law may be thus briefly 
defined : The strength or force of the current is equal to 
the electromotive force divided by the resistance in the 
circuit. 

The following general law has been established by 
Wheatstone : 

1. The electromotive force of a voltaic current varies 
with the number of the elements and the nature of the 



258 THE PRACTICAL ELECTROPLATER. 

metals and liquids which constitute each element, but is in 
no degree dependent on the dimensions of any of their 
parts. 

2. The resistance of each element is directly propor- 
tional to the distances of the plates from each other in the 
liquid, and is also inversely proportional to the surface of 
the plates in contact with the liquid. 

3. The resistance of the connecting wire of the circuit 
is directly proportional to its length and to its specific re- 
sistance, and inversely proportional to its section. 

RELATIVE CONDUCTIVITY OF METALS. 

BY L. WEILLER. 
Names of Metals. Conductivity. 

1. Silver, pure, 100 

2. Copper, pure, 100 

3. Copper, pure super-refined and crystallized, .... 99.9 

4. Silicium bronze (telegraphic), 98. 

5. Copper and silver alloy at 50 per cent., 86.65 

6. Gold, pure, 78. 

7. Silicic copper (with 4 per cent, of silicon), 75. 

8. Silicic copper (with 12 per cent, of silicon), 54.7 

9. Aluminum, pure, 54.2 

10. Tin, containing 12 per cent, of sodium, 46.9 

11. Silicium bronze (telephonic), 35. 

12. Plumbiferous copper, with 10 per cent, of lead, . . . 30. 

13. Zinc, pure, 29.9 

14. Phosphor bronze (telephonic), 29. 

15. Siliceous brass, with 25 per cent, of zinc, 26.49 

16. Brass, with 35 per cent, of zinc, 21.15 

17. Phosphide of tin, 17.7 

18. Gold and silver alloy, 50 per cent., 16.12 

19. Swedish iron, 16. 

20. Pure Banca tin 15.45 



PHOTO-ENGRAVING. 259 

RELATIVE CONDUCTIVITY OF METALS — CONTINUED. 
Names of Metals. Conductivity. 

21. Antimonous copper, 12.7 

22. Aluminum bronze, 10 per cent., 12.6 

23. Siemens's steel, 12. 

24. Platinum, pure, 10.6 

25. Amalgam of cadmium, with 15 per cent, of cadmium, . 12.2 

26. Mercurial bronze, Drosnier, . . . 10.14 

27. Arsenical copper, with 10 per cent, of arsenic 9.1 

28. Lead, pure, 8.88 

29. Bronze, with 20 per cent, of tin, 8.4 

30. Nickel, pure, 7.89 

31. Phosphor bronze, with 10 per cent, of tin, 6.5 

32. Phosphide of copper, with 9 per cent, of phosphorus, . 4.9 

33. Antimony, 3.88 

34. Mercury, 1.6 

35. Bismuth 1.2 

36. Graphite, .069 

For the many illustrations in the foregoing article the 
author is indebted to the eminent printing press manufac- 
turers, C. B. Cottrell & Sons. 



PHOTO-ENGRAVINGS FOR NEWSPAPERS. 

At the annual meeting in 1893 of the London Camera 
Club, Mr. H. Sutton read a paper about a new method 
of producing photo -blocks for newspaper work. He 
said the process was the result of the labor of years. 
He had been working at the problem since 1881, and 
only a short time previously had he obtained results suf- 
ficiently advanced to be worth bringing before the Camera 
Club. He had effected the direct conversion of photo- 



260 THE PRACTICAL ELECTROPLATER. 

graphs into blocks without intermediate conversion into 
fatty ink or bitumen images, followed by skilled etch- 
ing to get type high blocks. A process of this kind ought 
to give great impetus to the graphic arts. He simply 
electrotyped a relief image produced in the gelatine bromide 
film of an ordinary negative ; the electrotype is then at 
once passed on to the printer. A gelatine bromide nega- 
tive is developed with alkaline pyrogallol or quinol, then 
fixed in strong hyposulphite of soda and washed with care, 
so that it shall not absorb too much water. If it be now 
placed horizontally on a metal plate, and gradually heated 
to 2i2° Fahr. by the flame of a Bunsen's burner, the shad- 
ows of the image will be seen to run all over the plate. 
If, however, before development the negative had also been 
impressed under a crossed-line screen, so that the line 
screen and the picture would develop together, each little 
dot of the screen image would hold a certain amount of 
reduced silver, bearing some definite proportion to the 
action of light and development, and be surrounded by a 
fine line containing no silver where the opacity of the 
screen had prevented action. The reduced silver produces 
a certain amount of insolubility of the gelatine with which 
it is in contact, and the adjacent soluble gelatine, when 
heated as already described, runs beneath the insoluble 
gelatine by capillary action, thus producing dots and an 
image in relief. This capillary action is proportional in 
some way to the amount of reduced silver, and during the 
heating the two effects of relief and graduation are pro- 
duced at the same time. The electrotype is taken direct 
from the glass negative in relief. 



FRENCH VARNISH, 



"1£ T is important that every plater should know how to 
Jf prepare varnish. It is impossible to find in the 
^X market the various tones of varnish to color the 
brass. Herewith is submitted a cheap and prompt method 
of manufacturing and handling varnish : 

Two ounces of gum sandarac. 

One pint alcohol (the best obtainable). 

Ten drops of glycerine. 

The alcohol must entirely dissolve the gum sandarac. 
Mix the foregoing with any aniline colors, soluble in 
spirits, that the operator wants. For example, if it is de- 
sired to obtain a gold color on bronze, the latter must first 
be highly polished. Then take aurine yellow and bismarck 
brown. These aniline colors will give a nice gold color, 
dependent on the taste of the workman in the matter. It 
is of course understood that the two colors must be mixed 
with the ingredients mentioned above. 

If a nice copper color is wanted use the mixture of 
gum sandarac, alcohol and glycerine, with the addition of 
eosine, safranine and napoline. 

If a nice black color, like enamel, is required use the 
same formula, and add black negrosine. 



262 THE PRACTICAL ELECTROPLATER. 

Different colors can be obtained by aniline. When 
purchasing be sure to ask for aniline colors that will dis- 
solve in alcohol. For instance, blue, green and purple, &c. 
Each of these must be mixed with the gum sandarac, 
alcohol and glycerine. The aniline must be placed in a 
small dish with a few drops of glycerine and stirred thor- 
oughly with a finger until dissolved ; then put in the gum 
sandarac. The color to be obtained depends on the work- 
man. The work must be placed in an oven after it has 
been varnished. If it is a small piece, it can be heated by 
an alcohol or gas lamp. 

If the work is trimmings, like buttons, &c, put it in a 
wire basket, dip it in the varnish, and shake it well. Then 
put it in a sieve and immediately afterward in an oven. 

Transparent Varnish. 
If it is desired to prepare transparent varnish for avoid- 
ing tarnish on silver take the best and strongest alcohol on 
the market and dissolve the gum sandarac. Then dilute 
the mixture so that it can pass through a filter. When it 
has passed through the latter the mixture is ready for use. 
The gum sandarac must have a clear grain and should not 
be dirty. Silver goods thus varnished must be entirely free 
of grease. The most reliable way of lacquering silver is to 
take a piece of wadding and wash the surface of the article 
to be coated with the mixture. 



REFINING SWEEPS. 



L^ 



NDER this head the economical side of the work 
carried on in jewelry and other factories is 
treated in detail. The chief safeguard of the 
jeweler against loss is economy. In the various handlings 
of the auriferous metal, annealing, filing, lapping, polishing, 
&x., small portions, according to the work, are detached. 
Waste must consequently be avoided on all occasions. 

A few remarks anent economizing filings (or sweeps) 
will prove of value and of interest. Great difficulty is ex- 
perienced in keeping sweeps free from impurities, which is 
shown in the loss ensuing when they are collected, although 
this may be done with much care. 

The gold is weighed out for the workman, each man 
being responsible for his allotment. The worker has to 
account for the quantity given to him, the only allowance 
made being the usual one of six grains or more to the 
ounce. This allowance is a form of waste. 

Filings undergo various treatments in factories, each 
shop having its own method of recovery. Much knowl- 
edge on the subject is yet to be garnered. Workmen 
should never be allowed to turn in their filings in a dirty 



264 THE PRACTICAL ELECTROPLATER. 

condition. Such a practice will inevitably cause loss. 
Sifting and examining filings should be done before weigh- 
ing in. A good method is to take an iron ladle and treat the 
filings as follows : Sift carefully, through a fine sieve, let- 
ting the filings fall on paper provided for the purpose ; 
then put them into the iron ladle and heat till all or- 
ganic matter is destroyed. When the filings have cooled 
off run a magnet through, to gather any iron or steel 
filings present. The workmen should perform this duty 
and a close eye should be kept on the operation. 
One method of collecting filings is to take 

Twelve ounces filings or gold dust. 
Two ounces carbonate of potash. 
One ounce of common salt. 

This solution is mixed with the filings and placed in a 
crucible. Then put a layer of common salt upon it and put 
it in the furnace. No more of the mixture should be put in 
the crucible than will fill it to within an inch of the top, as 
it rises in melting and may flow over. 

When the fire is at its best continue the heat for about 
half an hour more, and on the expiration of that time draw 
the crucible and place it on one side to cool. Then break 
it at the bottom with a hammer, and the gold will be found 
at the bottom. Add a little saltpetre now and then, in order 
to refine the mass thoroughly. Care must be exercised in 
doing this, as it may flow over the pot and take some of the 
gold with it. If overflowing is likely to occur apply a little 
common salt, which will stop it. 

The accumulation of gold, or button, as it is frequently 
termed, will consist of a mixture of gold, silver and copper, 



REFINING SWEEPS. 265 

and maybe melted with a flux and poured into an ingot mold 
and worked up after it is assayed. Sal-enixum is said to be 
better than saltpetre, because it does not cost as much, and 
restrains the flux and filings from rising to the top of the 
crucible, something the saltpetre does not do. 

Another method followed is to place the filings in a com- 
mon crucible with a little flux, say, of carbonate of soda 
or potash. When the filings are well melted withdraw 
the crucible and pour its contents into a casting mold. 

When withdrawn from the casting mold the filings, 
now in the form of a bar, are ready to be disposed of to 
the refiner, or the bar may be exchanged for new metal. 
The author sends his gold obtained from removing the 
green from jewelry and from old gilding, after smelting it, 
to the Government assay office ; but the charges are so 
light, a few dollars on $400 worth of gold, that it does not 
pay to refine filings or gold sediment. It should be noted 
that the Government assay office will not take less than 
$100 worth of gold. 

If this method is followed by jewelers they will find 
that they will not suffer so much loss through having had 
a poor or indifferent working gold, for no filings will be in 
the bar. Filings are the chief cause of impure gold, be- 
cause they contain solder and other trimmings, which the 
neglectful or careless workman has let fall in and has not 
removed. For instance, it is unfit for casting Tiffany rings 
and other work, consequently the workman should exercise 
much care with this kind of work. If necessary at any 
time to cast work it will be found advisable to use new 
bar gold. The unworkable qualities of impure gold are to 



266 THE PRACTICAL ELECTROPLATER. 

be determined more from the presence of filings than from 
any other cause. 

Mention has been made above of the sweeps burning 
furnace to be used in refining. An illustration of the 
furnace is given herewith, accompanied by a clear de- 
scription of it and instructions how to use it. 

The sweeps burner is a gas blast furnace for burning 
sweeps to ashes, and is especially designed for jewelry fac- 
tories, though used for other purposes, such as the melting 
of soft metals, where it is necessary to draw off poisonous 
or disagreeable fumes. The iron caldron or pot D rests 
upon the top rim of the lining, which is a solid firebrick 
cylinder incased in iron, E, and is heated by a burner 
which distributes the heat evenly around the pot. The 
combustion chamber under and around the pot is com- 
pletely shut off from the upper part of the pot. The prod- 
ucts of the combustion are injected into the stove pipe H 
by the pipe G, and the smoke or fumes which rise from the 
pot into the upper part of the hood A are rapidly expelled 
through the pipe which connects with the chimney. 
The door C gives access to the pot for changing it. 
To remove the pot or insert it, the front half of the hood 
hinged on top is opened upward. Connection with gas is 
by a three-eighth inch pipe, K, to the valve I. The air pipe 
must be brought down to or near the floor and connected 
with the air pipe L on the furnace by an upward turn, as 
shown in the illustration. 

The furnace is intended to receive the floor sweeps 
every day, as soon as gathered. When the caldron is full 
and well packed the furnace is lighted by : First, turning 




Sweeps Burning Furnace. 



268 THE PRACTICAL ELECTROPLATER. 

on the air cock full ; second, holding a lighted paper torch 
into the lighting hole and then turning on just enough (and 
no more) gas as is needed to produce a steady combustion. 
Only a very small blue flame should issue from the lighting 
hole. When thus adjusted, the lighting hole is closed by 
a fireclay plug provided for it. 

To save gas in burning sweeps the use of some cheap 
petroleum oil, kerosene, or naphtha is recommended. With 
every charge use about a pint of the oil to moisten it, 
sprinkling it evenly over the top of the charge, or mixing 
it with the sweeps. 

It is then only necessary to get the caldron cherry red, 
when the sweeps will burn to ashes without the further use 
of gas. A good plan is to light the furnace late in the 
afternoon, get the caldron cherry red, and, turn off both 
gas and air (gas first). The oil mixed with the sweeps will 
then complete the reduction to ashes. 




RECOVERING JEWELERS' WASTE. 




^ ^ AREFULLY gather and burn in a closed iron pan 
or other suitable vessel any sediment that has 
accumulated in the scratch brush and polishing 
boxes, lappers' cotton waste, &c. This will reduce the 
bulk of the waste and do away with organic matter. Do 
the burning carefully, so that the smaller gold particles do 
not ascend the chimney with the draft. Hence it will be 
preferable to have a lid to the pan. When the burning has 
gone far enough, and the operation is finished, run the re- 
maining ash through a sieve. Pound the refuse remaining 
in the latter and sift once more. The refuse is then ready 
for the test. If the gold is to be collected take 

Eight ounces polishings, 
Four ounces carbonate of potash, 
Two ounces common salt, and 
One ounce sal-enixum. 

The above ingredients should be well mixed with the 
polishing ashes. The material being drier and lighter than 
filings a greater proportion of salts is necessary, to bring 
down the gold into a button. Place the mixture in the 
crucible and treat as has been advised for collecting filings, 
with the difference that, as the mixture sinks to the bottom 



270 THE PRACTICAL ELECTROPLATER. 

in this process, more of the poiishings mixture must be 
added from time to time till the crucible holds as much as 
possible. When fused add a few crystals of saltpetre now 
and then ; a quicker fusion is had by adding moisture. The 
action of the saltpetre must be carefully watched. If likely 
to overflow throw in a small quantity of salt, as mentioned 
under " Refining Sweeps." This will force the flux down. 
If enough saltpetre has been added to the fused mass it will 
take off any iron, steel, &c, present. To get the gold use 
a hammer, as mentioned in the previous article. 

Mixing this kind of waste with floor sweepings has 
been recommended, a plan to which there is great objection. 
This sort of waste is usually rich in gold, and it is hard 
to mix it thoroughly with so large an amount as ordinary 
floor sweeps usually come to, so as to realize its value, a 
part of which would surely be lost. Consequently there 
should be three distinct methods of treatment for recover- 
ing gold from waste. The first should take in lappers' 
cotton waste and the sediment accruing in the poiishings 
and scratching boxes and similar waste. The second should 
embrace the water in which hands are washed, old solu- 
tions, worn out acid coloring mixtures and rinsing waters, 
together with other waters made use of. The third should 
comprise the sweeps, i. <?., sweepings from the floor, old 
crucibles, ashes and cinders, and refuse of any sort worth 
keeping. The dross from fluxes should also be preserved, 
separately, and put through the fire when enough has been 
gathered. 



REFINING AURIFEROUS METAL 



zi|f>T" ^HIS is not carried on by workers in gold on an 
5 I (L) extensive scale, nor is there any advantage from 
J1L the pecuniary standpoint in doing so, as too 
much cost is incurred for apparatus, and there is no appre- 
ciable return. Another thing to be considered is that the 
refiner is able to do it better and cheaper. 

To separate auriferous metal from metal with which it 
is alloyed, the filings must be gathered as pointed out in the 
preceding articles on refining sweeps and recovering waste. 
To effect the separation of the alloy from the auriferous 
metal, submit the composition to the action of nitric acid. 
As the alloy usually consists of such proportions that the 
acid cannot do its work properly, it is necessary to remelt 
the bar of auriferous metal and add thereto, if of nine or 
lower karat quality, half its weight in silver, with a little 
flux. When the mixture is incorporated pour it into a deep 
vessel of water, stirring it circularly while doing so. The 
auriferous metal will be found in small grains at the bot- 
tom of the vessel. These grains must be gathered care- 
fully and put in an evaporating dish or Florence flask made 



272 THE PRACTICAL ELECTROPLATER. 

of heat resisting glass, free of lead and treated with nitric 
acid as follows. A mixture of 

One ounce auriferous metal, 
One ounce nitric acid, and 
Two ounces of water 

should be permitted to stand for a few hours. At the end 
of the operation raise the temperature of the mixture to 
promote chemical action. The component parts, except the 
auriferous metal, will dissolve, and the latter will be dis- 
cerned as a dark brown powder at the bottom of the evap- 
orating dish or Florence flask. 

To remove the baser alloys, pour the above solution, 
with the silver, copper, &c, into another jar, which con- 
tains a large quantity of salt water. Throw the acid in, 
and the silver contained in the solution will precipitate to 
the bottom. When the liquid is not limpid, but is white, 
like milk, it is proof that more salt is needed in the water. 
When the water is limpid throw it away, and chloride of 
silver will be the residue. Copper will be of such small 
amount that there will be no necessity to collect it. 
Then add fresh nitric acid to the auriferous metal and 
apply heat. If the acid has no effect on the auriferous 
metal pour it off and wash the metal with hot water, for 
the purpose of removing traces of alloy in any interstices. 
The auriferous metal will then be pure, and all that is nec- 
essary is to melt it with borax or potash. 

If all the alloy is not removed from the auriferous 
metal it is likely to be brittle when worked again. 



TESTING GOLD AND SILVER. 



Testing Gold. 

ZT is always advisable to have a solution at hand by- 
using which it may be ascertained beyond doubt 
whether the articles are of gold or base metal. A 
solution for this purpose is composed of 

Two ounces of nitric acid, 
Four drams of water, and 
One scruple of muriatic acid. 

Mix these ingredients well and place in a stoppered 
glass bottle or other convenient vessel, so that the mixture 
may be ready for use when needed. All that is necessary 
in testing with the aid of this solution is to touch the gold 
with the stopper and after doing so observe the action of 
the acid. If no effect is produced it does not follow that 
the gold tested is genuine — the article may be thickly 
plated. The best method is to gently file a small part and 
drop the acid on the spot that has been filed. Merely rub- 
bing the file over will do. If base metal is present the 
fraud will be discerned immediately. Gold over nine karats 
will stand this test. Anything inferior will be shown up by 
the acid boiling green. 

Testing Silver. 

It will be found much more difficult to test silver than 
gold. The only way to make sure is to place the silver in 



274 THE PRACTICAL ELECTROPLATER. 

the cupel so as to obtain an assay by means of the muffle. 
A practical silver worker will recognize good silver by 
scraping the surface of the metal. Good silver scrapes 
softly. German silver is the reverse, as it scrapes hard 
and the shavings are brittle. If a little potassium sulphide 
is placed on the silver the latter will tarnish, and german 
silver will not. 



COLORS OF GOLD. 

To obtain yellow gold take 24 parts of pure or fine 
gold ; red gold, 6 parts of copper and 18 parts of fine gold ; 
blue gold, 6 parts of iron and 18 parts of fine gold ; white 
gold, 12 parts of silver and r2 parts of fine gold; green 
gold, 6 parts of silver and 18 parts of fine gold. For the 
white gold platinum or fine silver may be used. Red and 
white golds are usually employed for flowers, and green for 
leaves, stems and sprays being made of yellow or fine gold. 
Blue is used for ornamentation. 




ASSAYING AND TESTING 
SWEEPS. 



JT has been mentioned elsewhere that the cost of appa- 
ratus for refining sweeps is ordinarily too much for a 
jeweler. However, a method is given below by- 
carrying out which a jeweler may ascertain the value of 
his sweeps. It will be found very simple and at the same 
time of considerable value. Two assays must be taken, the 
first being merely a preliminary. For instance, half an 
ounce of sweeps ashes treated as before mentioned, that is, 
well burned out, a quarter of an ounce of litharge and half 
an ounce of flux should be smelted in a crucible over a very 
hot fire. If very much oxide is present a little more flux is 
necessary. If, on the contrary, the litharge produces too 
much metal, reduce the lead left by the litharge in the bot- 
tom by means of saltpetre. Litharge is a yellow powder, 
called peroxide of lead. The litharge is used for the pur- 
pose of collecting the fine powdered (or dust) gold con- 
tained in the ashes, and is mixed with the flux and gold 
ashes and placed in the crucible preparatory to smelting. 
When smelted thoroughly the gold will form in a button at 
the bottom of the crucible. Let it cool and then break the 



276 THE PRACTICAL ELECTROPLATER. 

bottom of the crucible. Take out the button and place it 
in a cupel. Then place the latter in a refining muffle. 
After a short time a small globule of silver and gold will 
be found in it. This may be separated, as previously men- 
tioned, by the aid of nitric acid. 

If a jeweler has no facilities for refining sweeps a small 
quantity can be refined in a crucible by adding corrosive 
sublimate or sulphide of antimony. This must be burned 
until the fumes disappear. This operation is very un- 
healthful, but is quite often used by jewelers who carry on 
small businesses. It should be carried out in the open air 
where possible, for the purpose of avoiding the bad effect 
of the noisome fumes arising from the corrosive sublimate 
or sulphide of antimony while the burning is going on. 




ASSAYER'S WEIGHT. 




S is well known a karat is not an absolute weight 
as far as gold is concerned, being only the 
twenty-fourth part of a unit, whether that unit 
is a pound, an ounce, a pennyweight or a grain. It is used 
by jewelers to denote the purity of gold, and is divided into 
four grains, each of which is again divided into four quarters. 
The quarters are once more divided into as many sub- 
divisions as are necessary. The assay weight being a pound 

the karat would be represented thus : 

Dwts. Grs. 

Karat of a pound 10 o 

Grain of a pound 2 12 

Quarter grain of a pound o 15 

Karat of an ounce o 20 

Grain of an ounce o 5 

Quarter grain of an ounce o \% 

According to the above table the quarter grain is 
really 1% grains troy. 

TABLE OF WEIGHTS. 

Ozs. Dwts. Grs. 

Twenty-four karats of given dimensions will weigh 100 

Eighteen « " « " o 17 12 

Fifteen « " « " o 16 o 

Twelve « u t< « o 14 12 

Eight « " « « o 13 o 



278 



THE PRACTICAL ELECTROPLATER. 
GOLD ASSAYING REPORT. 



1,000th parts. 


Fine Gold 


in Pounds 


Troy. 


No. of Karats. 


Parts of fine 


gold. 


Ozs. 


Dwts. 


Grs. 


Karats. 


1000 




12 








24 


959 




11 


10 





23 


916 




11 








22 


834 




10 








20 


75o 




9 








18 


709 




8 


10 





17 


667 




8 








16 


625 




7 


10 





15 


584 




7 








14 


542 




6 


10 





13 


500 




6 








12 


458 




5 


10 





11 


4i7 




5 








10 


375 




4 


10 





9 




FRENCH COLORING. 



IP 



^HE formula printed below was first brought out 
in France and has been in general use since its 
introduction. The work to be colored must be 
annealed on a clear fire, boiled in aquafortis pickle, and 
hung upon fine wire (platinum or silver). Have at hand 
some boiling water. When ready to begin take 

Eight ounces of salt, 
Eight ounces of alum, and 
Sixteen ounces of nitrate of potash. 

Pound in a mortar to a fine powder, thoroughly mixed, 
then put in a crucible, and add enough of the hot water to 
make the whole a thick paste. Heat slowly and stir with a 
wooden spoon. When it boils dip the work and leave it 
suspended a few minutes ; then take it out and immerse in 
some of the hot water. The color will ther y be taken 
off, so that the progress of the work may be noted. 

If the mixture shows an inclination to boil dry add a 
very small quantity of hot water for the purpose of thinning 
it ; but not while the work is hanging in it. Let the color 
boil slowly and steadily, and do not let the work stop in it 
too long at a time — five or six minutes at most, and that at 
the beginning. The following dips must be more frequent. 
Thin the coloring during the process. 

It will be found that when the work is first immersed it 



280 THE PRACTICAL ELECTROPLATER. 

will take on a nearly black color, and that on each subse- 
quent dipping it will become of a lighter hue until the color 
of fine gold is reached. Do not let the work remain in the 
coloring longer than twenty minutes. When this stage 
has been arrived at the surface will be uniform, and its 
dullness may be worked off by means of the scratch brush 
and soaproot water. Prior to each immersion rinse the 
work in fresh boiling water and then dry in sawdust. 
In Pforzheim another mixture is made of 

Seven ounces of salt, 

Five ounces of muriatic acid, and 

Fourteen ounces of nitrate of potash. 

These ingredients undergo the pounding in a mortar 
prescribed for the first formula, and should be kept clean. 
Take an evaporating dish and dry it well on a fire, after 
which put the coloring salts in, stirring thoroughly as men- 
tioned before. When dried fine and hot add the muriatic 
acid. When the color boils up take the work, quite free of 
grease or other dirt, and put it in the mixture for a few 
minutes. Keep the work moving while in the mixture and 
then withdraw it and plunge it into clean hot water. 

After this stage of the proceedings put 2 ounces of 
hot water in the color, and when the latter boils place the 
work in the mixture for another minute. Then rinse in 
fresh boiling water, as mentioned in the process for the 
first formula. The work will then be finished. 

If necessary, use the scratch brush and soaproot water 
to attain a high degree of brilliancy. It will be found that 
this method is a very quick one, but a great deal of prac- 
tice is necessary before one becomes an adept at coloring. 



ELECTRO-DEPOSITION ON 
GLASS. 






s-^HERE are many methods of doing this kind of 
<L) work, and patent after patent has been taken 
out for the purpose. Cursory mention of two of 
these methods has been thought sufficient. By the Pottier 
process the article is decorated with a paste composed of 
finely divided silver, plumbic chlorate and oil. It is then 
heated to a moderately high temperature, during which a 
strongly adherent film is produced, on which the electro- 
deposition can then be made with great facility. 

The process of John H. Scharling, of Newark, N. J., 
consists of a method of depositing different layers of metal, 
on the articles, and a new process of floating upon them a 
thin potash solution or other solution of silver, which de- 
composes itself, and forms a thin and translucent coating of 
silver, hardly perceptible, and upon which can be deposited 
by the electro-depositing process a second layer of either 
gold, platinum, silver or other metal. The potash solution 
consists of potash, nitrate of silver, ammonia, and milk 
sugar. The method of flowing the solution is a very eco- 



284 THE PRACTICAL ELECTROPLATER. 

nomical one, as a slight quantity of the potash solution can 
be used over and over again, while in the old process of 
dipping, in order to entirely immerse the article, a great 
quantity of the expensive solution was necessary. When 
the inner layer of silver has been formed upon the article a 
coating of gold can be deposited, followed by another layer 
of silver. After the article has been electro-deposited it 
can be polished and finished, any design may be painted 
on the oufer layer with a resist varnish, and then placed in 
an acid bath, whereby the outside silver coating not pro- 
tected or covered by the varnish will be eaten away, 
producing the design in clear and sharp outline and ex- 
posing the middle layer of gold or platinum. The varnish 
is then cleaned off and the exposed gold or platinum sur- 
faces are removed by any mechanical means, such as a 
scratch brush, and the metal so removed can be recovered 
by refining. 




SMALL OUTFITS FOR MANU 
FACTURERS. 



ANY manufacturers with small establishments 
have hesitated to purchase this work after 
L?^X / r*\^ inspecting the plant of the author, seem- 
ingly under the impression that too high an expense would 
have to be incurred in purchasing material wherewith to 
work. This is an error. For an outlay of about $15 to $20 
sufficient material may be obtained for a small plant, 
practical outfit for good plating consists of one penny- 
weight of gold for solution, one platinum anode (one 
pennyweight), one small foot lathe, two scratch brushes 
(one of one row and one of two rows), one small evapo- 
rating dish for preparing the chloride of gold, one Bunnell 
battery, one evaporating dish (porcelain) of about half a 
gallon capacity for holding the solution, and a gas or kero- 
sene stove. Keep the solution at the boiling point. There 
must also be conducting wires from the battery to the 
solution and thin copper binding wire. 



286 THE PRACTICAL ELECTROPLATER. 

There is illustrated herewith a new battery, a substi- 
tute for the well-known Bunsen, which has been invented 
by J. H. Bunnell. 

This battery is perfectly adapted to use, and gives the 
best of results with any acid solutions. It is equally avail- 
able for use as a Fuller battery, where the zinc is always 



Bunnell Combination Battery. 

kept amalgamated by the presence of a little mercury 
in a porous cup, or it may take the place of Bunsen, car- 
bon, Grove and nitro-chromic batteries, or any acid battery 
using special solutions. The carbon element consists of 
fourteen round carbons, all attached to the porcelain cover 
and connected to a binding post. This battery is per- 
fectly adapted to use for electroplating, and gives good re- 
sults with any acid solutions. Its great carbon surface and 



SMALL OUTFITS FOR MANUFACTURERS. 287 

its better proportion obtained in the quantities of solutions 
by the large size of the porous cup, its use of mercury in 
the porous cup, thereby keeping the zinc thoroughly amal- 
gamated, the avoidance of evaporation by having a com- 
plete porcelain cover, and its convenient and cheap renewal 
of parts make it a valuable universal battery for utmost 
power with chromic, nitric, sulphuric or other strong acid 
solutions. 

The author has much pleasure in recommending this 
new Bunnell battery, inasmuch as in a small store or shop 
the fumes arising from the Bunsen or other batteries are 
very unhealthful. Nothing of the sort occurs with this 
new battery. 

For removing the green (see page 20) from small 
articles, a jar for instance, one cell is sufficient if the bath 
has been strengthened with cyanide of potassium to 30 
Baume. The poles should be reversed for the operation of 
removing the green ; for example, the conducting wire that 
connects the zinc should be attached to the sheet of copper, 
and the wire connected with the carbons should be attached 
to the suspending hook on which the goods are placed. If 
it is necessary to remove the green from a large quantity of 
goods increase the number of cells, connect the carbons 
together, and do the same with the zincs. If the current is 
weak, do not shake the goods. If the current is strong the 
goods must be well shaken. 

These rules apply also to gold and silver plating. If 
the current is strong and the articles are not shaken the 
latter will present a dark red color. This coloring depends 
a good deal upon the amount of surface of the anode im- 



288 THE PRACTICAL ELECTROPLATER. 

mersed in the solution. The anode is the sheet of platinum 
or gold attached to the wire connected with the carbon. 

For charging the battery half fill the jar with water 
and add sulphuric acid until from 20 to 25° Baume are 
reached. Add a pound of bichromate of potash. In the 
porous cup containing the zinc place a tablespoonful of 
mercury and fill with water. If it is desired to quicken the 
action of the battery add a small quantity of sulphuric acid 
to the contents of the porous cup. 

To renew the battery when the bichromate fluid has 
become black and the current given out is feeble, the jar 
and porous cup should each be washed out clean, care 
being taken, however, to save the mercury, which can be 
used again. The renewal is then a repetition of the charg- 
ing process described above. 




DIRECT CURRENT TRANS- 
FORMER. 



ANY manufacturers and platers try to utilize 
l^K^^\ the electric incandescent light current, un- 
«_As3L^ fortunately without success. The Crocker- 
Wheeler Electric Company has submitted to the author 




Direct Current Transformer. 

a direct current transformer or motor dynamo. The 
special function of this machine is to transform an avail- 
able existing condition of direct electrical pressure and 



2 9 o THE PRACTICAL ELECTROPLATER. 

volume into such a new condition as may be required for 
electroplating, up to pressure as high as 10,000 volts. 
This dynamo motor is able to run shop machinery and 
electroplating solutions, removing the green, silver strip- 
ping, etching, &c. The machine runs quietly on any cir- 
cuit without trouble, and delivers a current of any quantity 
and character, independent of the primary current. From 
the ordinary incandescent light circuit a small volume of 
current at a voltage of no may be transformed to a larger 
volume of current with a voltage of from 3 to 6 volts, thus 
making a saving of 50 per cent, over the old method of 
using the electric current in a large amount directly through 
a series of lamps or other resistance. 




PROBLEMS OF COMMERCIAL 
ELECTROLYSIS. 






5~^HE following article has been taken from a paper 
QJ read by Mr. J. Swinburne before the Institution 
of Electrical Engineers, London, and is repro- 
duced with the consent of that gentleman : 

It would be idle to attempt to go over the whole sub- 
ject of the technical applications of electrolysis, as, al- 
though this development of industry is of recent growth, 
it is already so extensive that many of its branches demand 
much discussion. 

There is a general feeling that there is a mine of un- 
told wealth in the application of electricity to metallurgy ; 
but chemists are not generally electricians, and electricians 
are seldom chemists. 

However puzzling the theory of electrolysis may be 
for commercial purposes it may be regarded as involving 
no mystery. In fact, broadly speaking, we may disregard 
the electrical side of the question and look upon electrol- 
ysis as a method of oxidizing and reducing, and nothing 
more. It must be remembered, however, that there are 
often many ways of oxidizing the same substance. 



292 the practical electroplater. 

Aluminum. 

The extraction of aluminum has long been an im- 
portant problem. The old method was to replace aluminum 
in its chloride by means of sodium. This involves the 
manufacture of metallic sodium, and of the anhydrous 
chloride of aluminum. The anhydrous chloride cannot be 
obtained by evaporation of its solution, as the solution 
gives off hydrochloric acid and leaves alumina, otherwise 
the anhydrous chloride would be quite cheap. The extrac- 
tion of aluminum by ordinary means is still so expensive 
that electrical methods can compete. 

It seems to be impossible to deposit aluminum from 
any of its solutions, so fused salts have to be employed. 
The electrolytic processes differ in detail only. The elec- 
trolyte is cryolite, or a solution of alumina in cryolite. 
If cryolite is electrolyzed, aluminum is deposited and 
fluorine is presumably evolved at the anode, which is made 
of carbon. I have not seen any account of how the fluorine 
comes off. Yet in some processes it is stated that cryolite 
is electrolyzed by itself. In the Minet process the solution 
of oxide is employed and aluminum is deposited, and the 
anodes are burned away by the oxygen giving off, accord- 
ing to some accounts, carbon dioxide, but probably the 
monoxide in fact. The chief difficulties in the electrolysis 
of cryolite solutions are due to the cryolite itself, as it at- 
tacks all the substances commonly employed for making cru- 
cibles. It is therefore usual to use cast iron to make the 
containing vessels or vats, and to heat the electrolyte by 
electrical power from the inside. 

Minet uses iron vats and arranges a shunt current, 



MAGNESIUM. 293 

which makes the vats to some extent cathodes, so that they 
are not attacked by the electrolyte. Presumably fluorine 
is soluble in fused cryolite and attacks iron. By making- 
it a cathode it is always coated with aluminum, so that any 
fluorine is taken up in dissolving off some of this alumi- 
num. The importance of preventing the corrosion does 
not lie so much in the slight saving of iron as in the 
avoidance of any deposit of this metal in the aluminum. 
The great difficulty is to get the aluminum pure, and any 
face of iron reduces its value for most purposes very 
greatly. Minet reduces the melting point of the electro- 
lyte by the addition of common salt. In the Hall process, 
carried on at Pittsburg, the electrolyte is practically the 
same. Calcium fluoride is used to mix with the cryolite or 
calcium chloride. The Kleiner and, I believe, the Hall 
processes are carried on in England. The processes need 
not be discussed at any length here. There is still a great 
demand for cheaper aluminum ; and there is much to be 
done in making it pure. Aluminum has a strong affinity 
for silicon, and small percentages of silicon and iron are 
generally present and are very deleterious. 

Magnesium. 

This metal is closely allied to aluminum, and is similar 
with regard to its anhydrous chloride. There is not the 
same demand for it, as it either does not give remarkable 
alloys like those of aluminum, or they have not been inves- 
tigated. It is said to be made on the Continent by electro- 
lyzing the double chloride of magnesium and sodium or 
potassium obtained from the mother liquor after evaporat- 



294 THE PRACTICAL ELECTROPLATER. 

ing sea water. The double salt can apparently be rendered 
anhydrous without the formation of much magnesia. 

Zinc. 

Proposals have been made to deal with zinc ores elec- 
trically. The blend is to be roasted into sulphate and the 
solution dissolved and electrolyzed. A great difficulty 
arises in the deposition of the metal. It comes down in 
trees. Kiliani proposed to use high current densities, 
holding that zinc then comes down in the reguline state. 
Watt prefers to use acetate of zinc as the electrolyte ; 
and alkaline solutions, such as zincate of soda, have also 
been proposed. I am not aware that zinc has been de- 
posited commercially. Similar processes have been pro- 
posed for dealing with the silver zinc alloy produced in 
the Parkes or Karsten desilverization process. 

Lead. 

So far, little has been done in the way of dealing with 
lead ores electrically. It has been proposed to make 
anodes of galena and to work with lead nitrate as electro- 
lyte, but I have not heard that any such process has been 
carried out successfully. It is hardly likely that it could, 
as lead forms troublesome trees in acid solutions. Anyone 
who has worked with solutions of such salts as lead nitrate 
would be inclined to give up all hope of obtaining anything 
like a reasonably compact deposit of lead. 

The extraction of silver from lead by the Pattinson 
process is very cumbrous and roundabout, and is of course 
expensive. Keith started a works in America for desilver- 



GOLD AND SILVER. 295 

izing electrolytically. He used a solution of sulphate of 
lead in sodium acetate as electrolyte. Though the Keith 
process was brought out some ten years ago, it does not 
seem to have come into general use. The deposit of lead, 
even from such a solution as sodium plumbite, is very bulky 
and spongy, and is difficult to deal with, as it is apt to de- 
compose water and oxidize spontaneously during handling. 

Gold and Silver. 

Greenwood and others have proposed to make chlo- 
rine electrolytically for catching gold by the chlorine proc- 
ess. As this is exactly the same problem as making bleach- 
ing powder the same difficulties have to be overcome ; so 
it need not be discussed. 

Crookes's sodium amalgam for making the mercury 
ready to seize any particles of gold, and to keep it from get- 
ting " sick," can be replaced by making the mercury itself 
the cathode. It is questionable whether this would be 
worth while, as the sodium amalgam is very convenient. 

Crookes has recently brought out other electric gold 
processes. He finds that the particles of gold become 
amalgamated and collect and get caught in the mercury if 
the stamped quartz is washed in a weak solution of mer- 
cury salt, under the influence of an alternating current of 
small frequency. It is difficult to see how the alternating 
current works. Unless the current density or the resistance 
of the electrolyte is something fabulous there cannot be 
any current in the small particles of gold, as the minutest 
polarization would make all the electricity flow by the elec- 



296 THE PRACTICAL ELECTROPLATER. 

trolyte and not by the little pieces of gold, even though 
they are very much better conductors. 

Electro-Metallurgy of Copper. 

Electrolysis may be employed either in connection with 
the extraction of the copper from its ores, or in refining 
copper, especially when there is silver alone, or with gold in 
addition, to be extracted. 

In the first case — that of extraction of copper from 
pyrites — the ore may be converted into matt, and the matt 
can be cast into anodes, or the ore may be acted on by 
oxidizing solutions produced by electrolysis, or the two 
processes may be combined. 

In the first method the matt is cast into anodes, which 
are treated in baths of copper sulphate with copper cath- 
odes. The sulphides are attacked, sulphite of copper is 
formed, sulphur and impurities being left on the anode. 
The copper is deposited and iron remains in solution. The 
chief difficulties in connection with this process are that 
the anodes are brittle and troublesome, and are often eaten 
away unevenly, and the solution becomes richer and 
richer in iron salts. In addition to this, it is stated that 
the circulation of the iron salts must be avoided, otherwise 
ferric sulphate will be produced at the anode and reduced 
at the cathode ; and this process will go on wasting power 
over resistance. Some sort of diaphragm is therefore 
necessary. 

It must be pointed out that sulphuric acid can be made 
from the sulphur dioxide given off in the first roasting of the 
ores, or from the surplus ferrous sulphate. The ore can be 



ELECTRO-METALLURGY OF COPPER. 297 

roasted so as to give a good deal of soluble oxide of cop- 
per, which can be dissolved in the acid and treated electric- 
ally. Merely working with anodes is an incomplete process ; 
it is better to combine it with extraction by lixiviation. The 
solution after being in contact with the anode, so as to. contain 
ferric sulphate, is led to the ore. The ferric sulphate is re- 
duced and the copper and iron are said to be dissolved, and 
if there is oxide of copper it is taken up by sulphuric acid. 
This solution is led to the cathodes, where the copper is 
thrown down, and is then passed to the anodes, where the 
iron salt is oxidized. The various impurities and the 
precious metals are left with the sulphur of the anode. 
The sulphur is burned into sulphur dioxide, which goes to 
the chamber, and the silver, with the gold, if there is any, 
is extracted. The sulphate of iron can be burned into sul- 
phur dioxide, and the iron oxide sold as Venetian red. 
This is, in rough outline, the Marchese process. It may 
seem strange to those unacquainted with industrialchem- 
istry that if you want to extract copper you should also 
become involved in making sulphuric acid and red paint ; 
but in chemical works by-products must be utilized, so that 
often making one thing involves the production of a num- 
ber of other substances which have at first sight nothing 
to do with it. Messrs. Siemens & Halske avoid the neces- 
sity of making anodes of matt by employing carbon. The 
ferrous sulphate is thus oxidized into the ferric salt, and 
this is used to lixiviate the crushed and roasted ore. The 
solution is then led to the cathodes first, to take out the 
copper, then to the anode to oxidize it, and so on. 

In the Hopfner process chloride of copper is used in- 



298 THE PRACTICAL ELECTROPLATER. 

stead of sulphate. The action is stated to be as follows : 
Cupric chloride is formed at the anodes ; this is led to the 
matt, where it attacks the copper sulphide, forming cuprous 
chloride and sulphur ; and it is also said to dissolve the 
silver as well as the copper, which, if possible, would be a 
drawback. I do not know why the chioride should be pre- 
ferred to the sulphate, and no information is given as to 
what is done with the sulphur in the ore, and with the ex- 
cess of ferrous chloride that must be produced. 

The Marchese and Siemens & Halske processes are in 
commercial operation, and the electric extraction of copper 
is already a growing industry. The electromotive force 
necessary for this process is less than a volt ; so that, as- 
suming coal to be used, the electrical cost is 14s. 5d. per 
ton for the extraction of copper. I cannot give the whole 
cost, as that involves so many considerations. This figure 
will give copper smelters some idea of the saving of re- 
placing the ordinary refining process by electrolysis. 

In dealing with such a valuable substance as copper 
the time element must not be neglected. The interest on 
the money locked up in copper under treatment may be a 
very serious item. This is an objection of some weight in 
the case of matt anodes, which take some time to dissolve. 
The whole of the copper turned out is not obtained from 
the anodes ; but, taken all around, it may not be far wrong 
to assume that the copper takes about three months to pass 
through the works where matt anodes are employed. If 
the output is, say, 1,000 tons a month, the copper repre- 
sents a capital of some ^150,000, and the interest increases 
the cost of refining some 12s. a ton. 



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